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Geologic units containing conglomerate

Earth material > Sedimentary rock > Clastic rock
Conglomerate
A coarse-grained clastic sedimentary rock, composed of rounded to subangular fragments larger than 2 mm in diameter typically containing fine-grained particles in the interstices, and commonly cemented by calcium carbonate, iron oxide, silica, or hardened clay...
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Alabama
Attalla Chert Conglomerate Member of the Chickamauga Limestone (Ordovician)
Attalla Chert Conglomerate Member of the Chickamauga Limestone - conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized chert and quartz matrix; thin beds of gray-green or dusky-red shale common at base.
Attalla Chert Conglomerate Member of the Chickamauga Limestone (Ordovician)
Attalla Chert Conglomerate Member of the Chickamauga Limestone - conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized chert and quartz matrix; thin beds of gray-green or dusky-red shale common at base.
Chickamauga Limestone (Ordovician)
Chickamauga Limestone - Medium to dark-gray thick to thin-bedded partly argillaceous, locally fossiliferous limestone. Restricted to the western part of the Valley and Ridge province and Murphrees Valley and Wills Valley anticlines. Locally includes a thin interval of Attalla Chert Conglomerate Member at base. Attalla Chert Conglomerate - conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized matrix; thin beds of gray-green or dusky-red shale common at base.
Chickamauga Limestone (Ordovician)
Chickamauga Limestone - Medium to dark-gray thick to thin-bedded partly argillaceous, locally fossiliferous limestone. Restricted to the western part of the Valley and Ridge province and Murphrees Valley and Wills Valley anticlines. Locally includes a thin interval of Attalla Chert Conglomerate Member at base. Attalla Chert Conglomerate - conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized matrix; thin beds of gray-green or dusky-red shale common at base.
Chilhowee Group undifferentiated (Cambrian)
Chilhowee Group undifferentiated - light to medium-gray arkose, arkosic conglomerate, and discontinous mudstone overlain by greenish-gray mudstone with minor siltstone and sandstone; dominantly light-gray pebbly quartzose sandstone in upper part.
Cochran Formation (Cambrian)
Cochran Formation - poorly sorted arkosic sandstone and conglomerate containing interbedded greenish-gray siltstone and mudstone. The Cochran Formation is exposed only in northeastern Calhoun and northwestern Cleburne Counties.
Parkwood and Pennington Formations (Pennsylvanian-Mississippian)
Parkwood and Pennington Formations undifferentiated - Interbedded medium to dark-gray shale and light to medium-gray sandstone, locally contains lithic conglomerate, dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal.
Parkwood and Pennington Formations undifferentiated (Pennsylvanian-Mississippian)
Parkwood and Pennington Formations undifferentiated - Interbedded medium to dark-gray shale and light to medium-gray sandstone, locally contains lithic conglomerate, dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal.
Pottsville Formation (Pennsylvanian)
Pottsville Formation - Light-gray thin to thick-bedded quartzose sandstone and conglomerate containing interbedded dark-gray shale, siltstone, and coal. Mapped on Lookout Mountain, Blount and Chandler Mountains, and Sand Mountain northeats of Blount County, and on the mountains of Jackson, Marshall and Madison Counties north and west of the TN river.
Red Mountain Formation (Silurian)
Red Mountain Formation - dark-reddish-brown to olive-gray partly fossiliferous, mostly fine-grained sandstone interbedded with siltstone and shale; minor amounts of bioclastic limestone and conglomerate sandstone; includes hematitic beds and beds of ferruginous sandstone, outcrops in northeastern AL are finer grained and include more limestone.
Talladega Group; Butting Ram Sandstone (Silurian?-Devonian)
Butting Ram Sandstone - white to light-bluish-gray medium to coarse-grained, locally conglomeratic thick-bedded quartzose sandstone. Possible Devonian fossils.
Talladega Group; Lay Dam Formation (Silurian?-Devonian)
Lay Dam Formation (Talladega Group) - interbedded dark-green phyllite, medium-gray to light-brown and black metasiltstone, dark-green feldspathic metagraywacke, and light-gray and dark-gray medium to coarse-grained arkosic quartzite and metaconglomerate; graphitic phyllite common in upper part. In Cleburne and Calhoun Counties, rocks mapped as the Lay Dam include the Abel Gap Formation of Bearce (1973) and consist of interbedded greenish-gray metasiltstone and quartzite, black phyllitic metasiltstone, medium-gray to greenish-gray arkosic quartzite, and dark-gray pyritic quartzite. In Clay Chounty the upper part of the Lay Dam includes black graphitic sericite phyllite and slate reportedly containing plant fossils (Erin Slate Member).
Talladega Group; Lay Dam Formation, unnamed diamictite facies (Silurian?-Devonian)
Talladega Group; Lay Dam Formation, unnamed diamictite facies - Unnamed diamictite facies of Lay Day Formation in Coosa and Chilton Counties consists of cobbles and boulders of carbonate, pelitic rocks, quartzite, chert, felsic plutonic rocks, and gneiss in a metagraywacke matrix.
Weisner and Wilson Ridge Formations undifferentiated (Cambrian)
Weisner and Wilson Ridge Formations undifferentiated -- interbedded quartzose to slightly feldspathic sandstone and laterally continous conglomerate in ledge-forming units separated by greenish-gray silty mudstone.
Arkansas
Blakely Sandstone (Middle and Lower Ordovician) (Phanerozoic | Paleozoic | Ordovician-Early Ordovician-Middle)
Blakely Sandstone (Middle and Lower Ordovician)
Bloyd Shale, and Prairie Grove Member of the Hale Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Morrowan])
Bloyd Shale, and Prairie Grove Member of the Hale Formation
Cane Hill Member of Hale Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early [Morrowan])
Cane Hill Member of Hale Formation
Crystal Mountain Sandstone (Phanerozoic | Paleozoic | Ordovician-Early)
Crystal Mountain Sandstone
Missouri Mountain Shale and Baylock Sandstone (Phanerozoic | Paleozoic | Silurian)
Missouri Mountain Shale and Baylock Sandstone - The Baylock Sandstone is present only in the Cross, Cossatot, and Trap Mountains. Missouri Mountain Shale is mapped with Polk Creek Shale and Bigfork Chert in the area between Paron, Saline County, and Little Rock
Powell Dolomite (Phanerozoic | Paleozoic | Ordovician-Early)
Powell Dolomite
Arizona
Chinle Formation (Late Triassic)
Colorful mudstone, such as in the Painted Desert, and less abundant lenses of sandstone and conglomerate, deposited by a large river system. This unit typically is eroded into badlands topography and contains clays that are prone to shrinking and swelling. (210-230 Ma)
Cretaceous sedimentary rocks (Cretaceous)
Tan sandstone (Dakota Sandstone) overlain by gray shale (Mancos Shale); deposited in beach, river delta, and shallow sea settings. The Mancos Shale is overlain by the Mesaverde Group (map unit Kmv). This unit includes related sandstone and shale exposed near Show Low, Morenci (Pinkard Formation), and around Deer Creek south of Globe. (about 88-97 Ma)
Cretaceous to Late Jurassic sedimentary rocks with minor volcanic rocks (Late Jurassic to Cretaceous)
Sandstone and conglomerate, rarely forms prominent outcrops; massive conglomerate is typical near base of unit and locally in upper part. These deposits are nonmarine except in southeastern Arizona, where prominent gray marine limestone (Mural Limestone) forms the middle of the Bisbee Group. Sandstones are typically medium-bedded, drab brown, lithic-feldspathic arenites. Includes Bisbee Group (largely Early Cretaceous) and related rocks, Temporal, Bathtub, and Sand Wells formations, rocks of Gu Achi, McCoy Mountains Formation, and Upper Cretaceous Fort Crittenden Formation and equivalent rocks. (80-160 Ma)
Early Proterozoic metasedimentary rocks (Early Proterozoic)
Metasedimentary rocks, mostly derived from sandstone and shale, with minor conglomerate and carbonate rock. Includes quartz-rich, mostly nonvolcanic Pinal Schist in southeastern Arizona and variably volcanic-lithic sedimentary rocks in the Yavapai and Tonto Basin supergroups in central Arizona. (1600-1800 Ma)
Early Proterozoic metavolcanic rocks (Early Proterozoic)
Weakly to strongly metamorphosed volcanic rocks. Protoliths include basalt, andesite, dacite, and rhyolite deposited as lava or tuff, related sedimentary rock, and shallow intrusive rock. These rocks, widely exposed in several belts in central Arizona, include metavolcanic rocks in the Yavapai and Tonto Basin supergroups. (1650 to 1800 Ma)
Early Proterozoic quartzite (Early Proterozoic)
Brown to maroon, resistant quartzite and minor conglomerate of the Mazatzal Group, exposed primarily in the Payson area. (1650? -1700 Ma)
Early Tertiary to Late Cretaceous volcanic rocks (Late Cretaceous to Early Tertiary)
Rhyolite to andesite and closely associated sedimentary and near-surface intrusive rocks; commonly dark gray to dark greenish gray or greenish brown. In the ranges west of Tucson, this unit includes thick welded ash-flow tuffs. Volcanic rocks of this unit are inferred to be derived from vents and volcanoes above magma chambers that solidified to form the granitic rocks of map unit TKg. These rocks are restricted to southeastern Arizona except for a small outcrop near Bagdad. (50-82 Ma)
Holocene to middle Pliocene basaltic rocks (Middle Pliocene to Holocene)
Mostly dark-colored basaltic lava and cinders young enough that some original volcanic landforms are still apparent. Includes a small amount of andesite, dacite, and rhyolite. Rocks of this map unit are largely restricted to six areas widely distributed in Arizona: San Francisco and Uinkaret volcanic fields in northern Arizona (0-4 Ma); Springerville (0-4 Ma) and San Carlos (0-2 Ma) volcanic fields in east-central Arizona; and San Bernardino (0-1 Ma) and Sentinel (1-4 Ma) volcanic fields in southern Arizona. Rocks of this unit are also present in the extreme southwestern part of Arizona where they were erupted at the edge of the Pinacate volcanic field (0-2 Ma) in northwestern Sonora. (0-4 Ma)
Jurassic and Triassic sedimentary and volcanic rocks (Triassic and Jurassic)
Undivided massive quartz-feldspar porphyry of the Jurassic Planet Volcanics, quartz-rich metasandstone of the Jurassic Vampire Formation, and quartzite, phyllite, and fine grained, variably calcareous metasiltstone of the Triassic Buckskin Formation; exposed primarily in the Buckskin and Rawhide Mountains of western Arizona. This unit also includes sandstone and conglomerate beneath Jurassic volcanic rocks in the central Dome Rock Mountains. (160-240 Ma)
Jurassic sedimentary and volcanic rocks (Jurassic)
Sandstone and conglomerate derived from volcanic rocks with associated intermediate-composition lava flows, breccias, and tuffs. In southern Arizona this unit includes rocks of the Artesa sequence, Pitoikam Formation, Mulberry Wash volcanics, Rudolfo Red Beds, Recreation Red Beds, and Gardner Canyon Formation. In western Arizona it includes the Harquar Formation, rocks of Slumgullion, and related(?) unnamed units in the Kofa and Middle Mountains. This unit is characterized by maroon, brown, and purplish-gray volcanic-lithic sandstone and siltstone, with subordinate to abundant conglomerate, quartz-rich sandstone and sparse limestone. (150-170 Ma)
Jurassic to Cambrian metamorphosed sedimentary rocks (Cambrian to Jurassic)
Highly faulted and folded rocks of units Jv, J_, and Pz, deformed and metamorphosed in Jurassic, Cretaceous and Tertiary time. This unit is restricted to west-central Arizona. (160-540 Ma)
Jurassic volcanic rocks (Jurassic)
Massive quartz-feldspar porphyry, generally interpreted as thick, welded rhyolitic tuffs, with locally abundant lava, and sandstone and conglomerate derived from volcanic rocks. Rare eolian quartzite units are interbedded in southern Arizona. Includes Ali Molina Formation, Mount Wrightson Formation, part of the Canelo Hills Volcanics, Cobre Ridge tuff, Black Rock volcanics, Planet Volcanics, and equivalent rocks. (160-200 Ma)
Late to middle Miocene basaltic rocks (Middle to Late Miocene)
Mostly dark, mesa-forming basalt deposited as lava flows. Rocks of this unit are widely exposed south of Camp Verde (Hickey Formation basalts), in the Mohon Mountains north of Bagdad, "The Mesa" east of Parker, and at other scattered locations in western Arizona. Rocks of this unit were not tilted by middle-Tertiary normal faulting except in a narrow belt from north of Phoenix to the northwest corner of the state. (8-16 Ma)
Middle Miocene to Oligocene sedimentary rocks (Oligocene to Middle Miocene)
Con-glomerate, sandstone, mudstone, limestone, and rock-avalanche breccia (sheet-like deposits of crushed rock) deposited and tilted during widespread normal faulting and basin development. Sediments, mostly conglomerate and sandstone, are commonly medium to dark brown, reddish brown, or brownish gray; younger strata are generally lighter colors. Most deposits are 20 to 30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona. (11-32 Ma)
Middle Miocene to Oligocene shallow intrusions (Oligocene to Middle Miocene)
Generally very fine-grained, porphyritic rhyolite to dacite in small, irregular-shaped bodies formed as subvolcanic intrusions in volcanic fields of southern and western Arizona, or in concentrated zones of dikes in the Mohave and Black Mountains of northwestern Arizona. The unit consists of mafic tuff, breccia and shallow intrusions at Buell Park in northeastern Arizona. (14-35 Ma)
Middle Miocene to Oligocene volcanic and sedimentary rocks, undivided (Oligocene to Middle Miocene)
Sequences of diverse volcanic rocks with abundant interbedded sedimentary rocks. (11-32 Ma)
Middle Miocene to Oligocene volcanic rocks (Oligocene to Middle Miocene)
Lava, tuff, fine-grained intrusive rock, and diverse pyroclastic rocks. These compositionally variable volcanic rocks include basalt, andesite, dacite, and rhyolite. Thick felsic volcanic sequences form prominent cliffs and range fronts in the Black (Mohave County), Superstition, Kofa, Eagletail, Galiuro, and Chiricahua Mountains. This unit includes regionally extensive ash-flow tuffs, such as the Peach Springs tuff of northwestern Arizona and the Apache Leap tuff east of Phoenix. Most volcanic rocks are 20-30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona, but this unit includes some late Eocene rocks near the New Mexico border in east-central Arizona. (11-38 Ma)
Middle Proterozoic sedimentary rocks (Middle Proterozoic)
Red-brown shale and sandstone, buff to orange quartzite, limestone, basalt, black shale, and sparse conglomerate. This unit includes the Grand Canyon Supergroup, Apache Group, and Troy Quartzite. These rocks were deposited in shallow marine, coastal nonmarine, and fluvial settings. (700-1300)
Mississippian, Devonian, and Cambrian sedimentary rocks (Cambrian, Devonian, and Mississippian)
Brown to dark gray sandstone grades upward into green and gray shale, overlain by light to medium gray or tan limestone and dolostone. This unit includes the Tapeats Sandstone, Bright Angel Shale, Muav Limestone, Temple Butte Formation and Redwall Limestone in northern Arizona, and the Bolsa Quartzite, Abrigo Formation, Martin Formation, and Escabrosa Limestone in southern Arizona. These rocks record intermittent sea-level rise and inundation in early Paleozoic time. (330-540 Ma)
Moenkopi Formation (Early and Middle(?) Triassic)
Dark red sandstone and mudstone; includes gypsum beds in northwestern Arizona; deposited on a low-relief coastal plain. (230-245 Ma)
Morrison Formation (Late Jurassic)
Commonly cliff-forming, cross-bedded sandstone lenses alternating with slope-forming siltstone, mudstone and shale. Colors are highly variable, and include greenish gray, reddish brown, pink, white, and purple. Sands were deposited by braided streams with finer sediment representing overbank or lacustrine deposits. (145-160 Ma)
Oligocene to Paleocene[?] sedimentary rocks (Paleocene(?) to Oligocene)
Light colored, weakly to moderately consolidated conglomerate and sandstone deposited largely or entirely before mid-Tertiary volcanism and extensional faulting. Most sediment was deposited by early Cenozoic streams that flowed northeastward onto the Colorado Plateau from areas to the southwest that are now lower in elevation than the Plateau. Sediments of this map unit, other than the Chuska Sandstone in northeasternmost Arizona, are commonly referred to as "rim gravels" because they now rest on or near the Mogollon Rim, which is the southwestern edge of the Colorado Plateau. (30-65 Ma)
Permian to Pennsylvanian sedimentary rocks (Pennsylvanian to Permian)
Interbedded sandstone, shale, and limestone usually characterized by ledgy outcrops. Orange to reddish sandstone forms cliffs near Sedona. This unit includes Supai Group and Hermit Shale in northern Arizona and Naco Group in southern Arizona. It was deposited in coastal-plain to shallow-marine settings during time of variable and changing sea level. Rocks of this map unit in southern Arizona may be in part equivalent to Permian rocks of map unit P in central and northern Arizona. (280-310 Ma)
Pliocene to late Miocene basaltic rocks (Late Miocene to Pliocene)
Mostly dark, inconspicuously flat, low-lying or mesa-forming basalt deposited as lava flows. Rocks included in this unit are located almost entirely in the large volcanic fields south and west of Flagstaff, in smaller fields in northwesternmost Arizona, and in the Hopi Buttes volcanic field on the Navajo and Hopi Indian Reservations north of Holbrook. Original volcanic landforms have been obscured by erosion. (4-8 Ma)
Pliocene to middle Miocene deposits (Middle Miocene to Pliocene)
Moderately to strongly consolidated conglomerate and sandstone deposited in basins during and after late Tertiary faulting. Includes lesser amounts of mudstone, siltstone, limestone, and gypsum. These deposits are generally light gray or tan. They commonly form high rounded hills and ridges in modern basins, and locally form prominent bluffs. Deposits of this unit are widely exposed in the dissected basins of southeastern and central Arizona. (2-16 Ma)
Pliocene to middle Miocene volcanic rocks (Middle Miocene to Pliocene)
Rhyolite to andesite deposited as lava flows and related rocks associated with basaltic rocks of map units Tby and Tb. (2-12 Ma)
San Rafael Group (Middle to Late Jurassic)
Commonly cross-bedded, ledge-forming sandstone and slope-forming siltstone. Rock typically has a striped red and white aspect. The Carmel Formation and Entrada Sandstone are prominent members of this group. (Late to Middle Jurassic, about 160-180 Ma)
Shinarump Conglomerate Member, Chinle Formation (Late Triassic)
Basal conglomerate and pebbly sandstone of the Chinle Formation is relatively resistant to erosion and forms extensive benches in some parts of the Colorado Plateau. (210-230 Ma)
California
Cambrian marine rocks (Late Proterozoic to Middle Devonian)
Sandstone, shale, limestone, dolomite, chert, quartzite, and phyllite; includes some rocks that are possibly Precambrian
Carboniferous marine rocks, unit 3 (SE California Clastic Assemblage) (Late Devonian to Early Permian)
Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks
Carboniferous marine rocks, unit 4 (Eastern Klamath Mountains) (Mississippian to Early Permian)
Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks
Carboniferous marine rocks, unit 7 (Bishop) (Mississippian to Early Permian)
Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks
Cretaceous marine rocks (in part nonmarine) (?), unit 1 (Blythe) (Middle Jurassic(?) to Late Cretaceous)
Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges (?)
Cretaceous marine rocks (in part nonmarine), unit 1 (Coast Ranges) (Early to Late Cretaceous)
Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges
Cretaceous marine rocks (in part nonmarine) (?), unit 2 (Jacumba) (Late Cretaceous(?) to Miocene(?))
Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges (?)
Cretaceous marine rocks (in part nonmarine), unit 2 (West Walker River) (Triassic(?) and/or Jurassic(?))
Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges
Eocene and Paleocene marine rocks, undivided (Paleocene to middle Eocene)
Eocene marine rocks (Paleocene to Oligocene)
Shale, sandstone, conglomerate, and minor limestone; in part Oligocene and Paleocene.
Eocene nonmarine rocks, unit 1 (Northern and Central California) (Eocene)
Sandstone, shale, and conglomerate.
Eocene nonmarine rocks, unit 2 (Southern California) (middle to late Eocene)
Sandstone, shale, and conglomerate.
Franciscan Complex, unit 1 (Coast Ranges) (Jurassic to Cretaceous)
Franciscan complex: Cretaceous and Jurassic sandstone with smaller amounts of shale, chert, limestone, and conglomerate. Includes Franciscan melange, except where separated--see KJfm.
Jurassic marine rocks, unit 1 (Western Sierra Nevada and Western Klamath Mountains) (Triassic to Late Jurassic)
Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks
Jurassic marine rocks, unit 2 (Coast Ranges) (Late Jurassic to Early Cretaceous)
Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks
Jurassic marine rocks, unit 4 (Peninsular Ranges and Western Transverse Ranges) (Paleozoic(?) to Late Jurassic)
Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks
Jurassic marine rocks, unit 5 (Northern Sierra Nevada and Eastern Klamath Mountains) (Devonian to Late Jurassic)
Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks
Jurassic marine rocks, unit 6 (Mono Lake) (Ordovician(?) to Triassic(?))
Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks
Lower Cretaceous marine rocks (Early Cretaceous)
Lower Cretaceous sandstone, shale, and conglomerate
Lower Cretaceous marine rocks (?) (Cretaceous (?))
Lower Cretaceous sandstone, shale, and conglomerate (?)
Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains) (Jurassic)
Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks
Miocene marine rocks (Oligocene to Pliocene)
Sandstone, shale, siltstone, conglomerate and breccia; in part Pliocene and Oligocene.
Miocene marine rocks (?) (Miocene(?) or Pliocene(?))
Miocene marine rocks and Franciscan schist (Cretaceous(?) to Miocene)
Miocene nonmarine rocks (Oligocene to Pleistocene)
Sandstone, shale, conglomerate, and fanglomerate; in part Pliocene and Oligocene.
Oligocene nonmarine rocks, unit 1 (Northern California) (Oligocene to Miocene)
Sandstone, shale, and conglomerate; in part Miocene and Eocene.
Oligocene nonmarine rocks, unit 2 (Central and Southern California) (middle Eocene to early Miocene)
Sandstone, shale, and conglomerate; in part Miocene and Eocene.
Oligocene nonmarine rocks (?), unit 2 (Southeastern California) (Cretaceous(?) to Oligocene(?))
Paleocene marine rocks, unit 1 (Central and Southern California) (Paleocene)
Sandstone, shale, and conglomerate; mostly well consolidated
Paleocene marine rocks, unit 2 (Northern California) (Paleocene to late Eocene)
Sandstone, shale, and conglomerate; mostly well consolidated
Paleocene marine rocks, unit 3 (La Panza Range) (Late Cretaceous(?) to Eocene(?))
Sandstone, shale, and conglomerate; mostly well consolidated
Paleozoic marine rocks, undivided, unit 2 (Northern Mojave Desert and Southeastern Sierra Nevada) (Cambrian to Jurassic)
Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite
Paleozoic marine rocks, undivided, unit 3 (Eastern Sierra Nevada) (Late Proterozoic(?) to Mesozoic(?))
Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite
Paleozoic marine rocks, undivided, unit 4 (Western Sierra Nevada) (Ordovician to Triassic)
Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite
Paleozoic marine rocks, undivided, unit 9 (Western Klamath Mountains) (Devonian to Jurassic)
Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite
Paleozoic metavolcanic rocks, unit 1 (Eastern Klamath Mountains) (Devonian and Permian)
Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks
Paleozoic metavolcanic rocks, unit 5 (Mono Lake) (Triassic to Jurassic)
Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks
Permian marine sedimentary rocks, unit 1 (Death Valley and Mojave Desert) (Pennsylvanian to Triassic)
Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks
Permian marine sedimentary rocks, unit 2 (Northwestern Sierra Nevada) (Paleozoic or Mesozoic)
Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks
Permian marine sedimentary rocks, unit 3 (Northeastern Sierra Nevada) (Early to Late Permian)
Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks
Pliocene marine rocks (Miocene to Pleistocene)
Sandstone, siltstone, shale, and conglomerate; in part Pleistocene and Miocene.
Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene)
Pliocene and/or Pleistocene sandstone, shale, and gravel deposits; in part Miocene.
Precambrian rocks, undivided, unit 1 (Death Valley) (Early Proterozoic to Mesozoic)
Conglomerate, shale, sandstone, limestone, dolomite, marble, gneiss, hornfels, and quartzite; may be Paleozoic in part
pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous)
Undivided pre-Cenozoic metasedimentary and metavolcanic rocks of great variety. Mostly slate, quartzite, hornfels, chert, phyllite, mylonite, schist, gneiss, and minor marble.
Schist of various types and ages, unit 1 (Peninsular Ranges) (Triassic(?))
Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian
Silurian and/or Ordovician marine rocks, unit 2 (Bishop) (Late Cambrian(?) to Early Permian(?))
Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone
Silurian and/or Ordovician marine rocks, unit 3 (Eastern Klamath Mountains) (Ordovician to Early Devonian)
Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone
Tertiary-Cretaceous Coastal Belt Rocks (Late Cretaceous to Pliocene)
Sandstone, shale and minor conglomerate in coastal belt of northwestern California; included by some in Franciscan Complex. Previously considered Cretaceous, but now known to contain early Tertiary microfossils in places.
Tertiary nonmarine rocks, undivided (Paleocene to Pliocene)
Undivided Tertiary sandstone, shale, conglomerate, breccia, and ancient lake deposits.
Triassic marine rocks, unit 1 (Death Valley area and Mojave Desert) (Early to Middle Triassic)
Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks
Triassic marine rocks, unit 2 (Eastern Klamath Mountains) (Middle to Late Triassic)
Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks
Triassic marine rocks, unit 3 (Lake Almanor) (Permian to Jurassic)
Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks
Triassic marine rocks, unit 5 (Northern Sierra Nevada) (Middle to Late Triassic)
Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks
Upper Cretaceous and Paleocene marine rocks, undivided (Late Cretaceous to Paleocene)
Sandstone, shale, and conglomerate
Upper Cretaceous marine rocks (?) (Cretaceous)
Upper Cretaceous sandstone, shale, and conglomerate (?)
Upper Cretaceous marine rocks, unit 1 (Upper Great Valley Sequence) (Late Cretaceous)
Upper Cretaceous sandstone, shale, and conglomerate
Upper Cretaceous marine rocks, unit 2 (Klamath Mountains) (late Early to Late Cretaceous)
Upper Cretaceous sandstone, shale, and conglomerate
Colorado
Animas Fm (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Arkosic sandstone, shale, and conglomerate; contains abundant volcanic materials; Upper Cretaceous volcaniclastic McDermott Member at base
Arikaree Fm (Phanerozoic | Cenozoic | Tertiary)
Sandstone; contains abundant volcanically derived material
Basalt flows and associated tuff, breccia, and conglomerate of late-volcanic bimodal suite (Phanerozoic | Cenozoic | Tertiary)
Includes basalts of Hinsdale Fm in San Juan Mountains - Servilleta Fm in San Luis Valley and many other occurrences
Casper Fm and Lower part of Fountain Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
Casper Fm: sandstone
Chinle Fm (Phanerozoic | Mesozoic | Triassic)
Red siltstone, sandstone, and limestone-pellet conglomerate
Coalmont Fm (Phanerozoic | Cenozoic | Tertiary)
Arkosic sandstone, conglomerate, and shale; coal in lower part; in North Park
Cutler Fm (Phanerozoic | Paleozoic | Permian)
Arkosic sandstone, siltstone, and conglomerate
Dakota Sandstone and Burro Canyon Fm (Phanerozoic | Mesozoic | Cretaceous)
Sandstone, shale, and conglomerate. In northwest and west-central: Lower Cretaceous. In southwest: Lower and Upper Cretaceous.
Denver and Arapahoe Fms (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Sandstone, mudstone, claystone, and conglomerate; Denver is characterized by andesitic materials
Denver Fm or lower part of Dawson Arkose (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Arkosic sandstone, shale, mudstone, conglomerate, and local coal beds
Dolores Fm (Phanerozoic | Mesozoic | Triassic)
Red siltstone, shale, sandstone, and limestone-pellet conglomerate
Dolores Fm and Cutler Fm (Phanerozoic | Paleozoic Mesozoic | Permian Triassic)
Red siltstone, sandstone, and conglomerate
Dry Union Fm (Phanerozoic | Cenozoic | Tertiary)
Siltstone, sandstone, and conglomerate. Includes Wagontongue Fm (Miocene) in South Park
Eocene prevolcanic sedimentary rocks (Phanerozoic | Cenozoic | Tertiary)
South-central: Arkosic sand and bouldery gravel of Echo Park Alluvium. Southwest: includes Telluride Conglomerate and Blanco Basin Fm (arkosic mudstone, sandstone, and conglomerate)
Fountain Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
Arkosic sandstone and conglomerate
Frontier Sandstone and Mowry Shale Members of Mancos Shale, and Dakota Sandstone (Phanerozoic | Mesozoic | Cretaceous)
Locally includes, at base, Burro Canyon Fm (shale and sandstone) or, in western Moffat County, Cedar Mountain Fm (conglomerate and shale)
Hermosa Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian)
Arkosic sandstone, conglomerate, shale, and limestone; gypsum and salt in Paradox Member present in salt anticlines near Utah border
Huerfano Fm (Phanerozoic | Cenozoic | Tertiary)
Shale and sandstone. Includes Farisita Conglomerate in northwestern Huerfano County
Ingleside Fm and Fountain Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
Ingleside Fm: Limestone and calcareous sandstone. Fountain Fm: arkosic sandstone and conglomerate
Lodore Fm (Phanerozoic | Paleozoic | Cambrian)
Sandstone, shale, and conglomerate
Lykins Lyons and Fountain Fms (Phanerozoic | Paleozoic Mesozoic | Carboniferous Pennsylvanian Permian(?) Triassic)
Red siltstone, sandstone, and conglomerate
Madison Limestone and Lodore Fm (Phanerozoic | Paleozoic | Cambrian Ordovician(?) Silurian(?) Devonian(?) Carboniferous)
Maroon Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
Arkosic sandstone, siltstone, conglomerate, and local limestone
Middle Park Fm exclusive of Windy Gap Member (Phanerozoic | Cenozoic | Tertiary)
Arkosic sandstone and conglomerate containing abundant volcanic materials. Arbitrary line between Middle Park and Coalmont Formations is at Continental Divide
Minturn and Belden Fms (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian)
Minturn Fm in west-central and south-central and other units (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian)
Arkosic sandstone, conglomerate, shale, and limestone. Includes Madera Fm and Sharpsdale Fm of Chronic (1958) in Sangre de Cristo Range and Gothic Fm of Langenheim (1952) in Elk Mountains. Other units of Middle Pennsylvanian age.
North Park Fm (Phanerozoic | Cenozoic | Tertiary)
Sandstone, siltstone, and conglomerate; in North Park and Laramie basin
Ogallala Fm (Phanerozoic | Cenozoic | Tertiary)
Loose to well-cemented sand and gravel
Oligocene sedimentary rocks (Phanerozoic | Cenozoic | Tertiary)
Northwest: includes Duchesne River Fm (sandstone and shale; includes some rocks of Eocene age) and Bishop Conglomerate near Utah border. South-central: includes Florissant Lake Beds (tuffaceous shale and tuff) and Antero Fm (lime
Poison Canyon Fm (Phanerozoic | Cenozoic | Tertiary)
Arkosic conglomerate, sandstone, and shale
Quartzite, conglomerate, and interlayered mica schist (Proterozoic | Paleoproterozoic)
Quartzite, conglomerate, and interlayered mica schist
Rico and Hermosa Fms (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian)
Arkosic sandstone, conglomerate, shale, and limestone. Includes at base in some areas siltstone and shale of Molas Fm or Larsen Quartzite
Sangre de Cristo Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
Arkosic conglomerate, sandstone, and siltstone
Santa Fe Fm (Phanerozoic | Cenozoic | Tertiary)
Siltstone, sandstone, and conglomerate
South Park Fm (Phanerozoic | Cenozoic | Tertiary)
Arkosic sandstone and shale, volcaniclastic conglomerate, and andesite flows and breccia
Telluride conglomerate of Eocene prevolcanic sedimentary rocks (Te) and Cimarron Ridge Fm (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
In northwestern San Juan Mountains. Cimarron Ridge Fm: volcanic breccia and conglomerate.
Uinta Mountain Group (Proterozoic | Mesoproterozoic)
Quartzite, conglomerate, and shale
Upper part of Dawson Arkose (Phanerozoic | Cenozoic | Tertiary)
Arkosic sandstone, conglomerate, and shale. Includes Green Mountain Conglomerate south of Golden
Wasatch Fm (including Fort Union equivalent at base) and Ohio Creek Fm (Phanerozoic | Cenozoic | Tertiary)
Claystone, mudstone, sandstone, and conglomerate
Weber Sandstone and Maroon Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
White River Fm or Group (Phanerozoic | Cenozoic | Tertiary)
East: Ashy claystone and sandstone. Includes Castle Rock Conglomerate in region southeast of Denver. Northwest: Ashy claystone in North Park
Wingate Sandstone and Chinle Fm (Phanerozoic | Mesozoic | Triassic)
Connecticut
Clough Quartzite (Silurian)
Clough Quartzite - White, medium-grained, glassy to granular, well-layered quartzite and muscovitic quartzite, locally with garnet; conglomeratic (commonly with tourmaline) in lower part.
East Berlin Formation (Lower Jurassic)
East Berlin Formation - Maroon siltstone, silty and sandy shale, and fine-grained silty sandstone, generally well laminated and commonly well indurated, alternating with dark fissile shale; dolomitic carbonate common in cement, concretions, and thin argillaceous laminae. Local arkose; grades eastward into coarse conglomerate close to eastern border fault. The East Berlin Formation of the Hartford basin contains eight facies: trough cross-bedded sandstones, horizontally stratified sandstones, interbedded sandstones and mudrocks, ripple cross-laminated siltstones, black shales, stratified mudrocks, disrupted shales, and disrupted mudstones. These facies are interpreted as a continental depositional system and are divided into two assemblages. Sandflat/alluvial plain facies assemblage (sandstones and siltstones) is composed of sheet-flood deposits. The lacustrine assemblage (shales and mudrocks) represents a saline lake-playa system (Gierlowski-Kordesch and Rust, 1994).
New Haven Arkose (Upper Triassic; possibly Lower Jurassic at top)
New Haven Arkose - Red, pink, and gray coarse-grained, locally conglomeratic, poorly sorted and indurated arkose, interbedded with brick-red micaceous, locally shaly siltstone and fine-grained feldspathic clayey sandstone.
New Haven Arkose plus Buttress Dolerite (Upper Triassic; possibly Lower Jurassic at top plus Middle? Jurassic)
New Haven Arkose plus Buttress Dolerite - New Haven Arkose - Red, pink, and gray coarse-grained, locally conglomeratic, poorly sorted and indurated arkose, interbedded with brick-red micaceous, locally shaly siltstone and fine-grained feldspathic clayey sandstone. Buttress Dolerite (Middle? Jurassic) - Dark-gray to greenish-gray (weathers brown or gray), medium- to fine-grained, commonly porphyritic, generally massive with well-developed columnar jointing, grading from basalt near contacts to fine-grained gabbro in the interior, composed of plagioclase and pyroxene with accessory opaques and locally devitrified glass, quartz, or olivine.
Portland Arkose (Lower Jurassic)
Portland Arkose - Reddish-brown to maroon micaceous arkose and siltstone and red to black fissile silty shale. Grades eastward into coarse conglomerate (fanglomerate).
Shuttle Meadow Formation (Lower Jurassic)
Shuttle Meadow Formation - Maroon to dark-gray, silty shale, siltstone, and fine-grained silty sandstone, generally well and thinly laminated. In the southern part of the State includes a layer, up to 5 m thick, of blue, commonly sandy, fine-grained limestone or dolomitic limestone, grading laterally into calcareous siltstone. Coarser and more arkosic to east and south, grading into conglomerate near the eastern border fault.
Georgia
Chilhowee Formation (Cambrian)
Chilhowee Formation, includes Weisner Formation of Kesler, 1950
Conglomerate (Precambrian-Paleozoic)
Conglomerate
Lookout Sandstone; Sewanee Sandstone (Pennsylvanian)
Lookout Sandstone; Sewanee Sandstone
Pennsylvanian undifferentiated (Pennsylvanian)
Pennsylvanian undifferentiated
Slate/ Quartzite/ Conglomerate (Precambrian-Paleozoic)
Slate/ Quartzite/ Conglomerate
Undifferentiated pelitic rocks (Precambrian-Paleozoic)
Undifferentiated pelitic rocks, includes mica schists, metasiltstones, metaconglomerates, and metagraywackes
Idaho
Arenite, carbonate, conglomerate, and shale; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic)
Uppermost Younger Precambrian massive quartzite with carbonate beds of central and southeastern Idaho; overlies (Z1s).
Arenite, shale, dolostone, siltstone, conglomerate, chert, and limestone; Lower Ordovician marine outer continental-shelf deposits; central Idaho (Early Ordovician)
Lower Ordovician dolomite, nodular cherty limestone, and intraformational conglomerate.
Conglomerate, sandstone, and siltstone; Eocene to Late Cretaceous alluvial-fan deposits; east-central Idaho, Cordilleran fold-thrust belt, piggyback basins (Eocene to Late Cretaceous )
Lower Tertiary to Upper Mesozoic breccia, conglomerate and sandstone; syntectonic in part.
Dolostone, arenite, conglomerate, and chert; Silurian to Middle Ordovician marine outer continental-shelf deposits; east-central Idaho (Silurian to Middle Ordovician)
Silurian to Middle Ordovician marine carbonate-to-clastic strata of east-central Idaho.
Dolostone, limestone, arenite, chert, and conglomerate; Ordovician marine continental-shelf deposits; southeastern Idaho (Ordovician)
Ordovician marine dolomite, quartzite, and limestone; subdivisions are (Ou and Ol).
Dolostone, limestone, sandstone, shale, and conglomerate; Devonian marine continental-shelf deposits; east-central and southeastern Idaho (Devonian)
Devonian bedded dolomite and limestone interval of eastern and southern Idaho.
Dolostone, shale, arenite, siltstone, limestone, conglomerate, and chert; Ordovician and Cambrian marine outer continental-shelf deposits; central Idaho (Ordovician and Cambrian)
Ordovician and Cambrian thrusted dolomite, siltstone, and quartzite of central Idaho.
Limestone, shale, siltstone, chert, and conglomerate; Mississippian western turbiditic flysch to eastern shallow-water carbonates; east-central Idaho (Mississippian)
Mississippian shallow-water carbonate-to-clastic sequence of east-central Idaho.
Metasedimentary and metavolcanic rocks; Permian greenschist-facies rocks; western Idaho, Blue Mountains island-arc complex (Late Permian)
Upper Permian submarine volcanic complex in the Snake Canyon of western Idaho.
Metavolcanic and metasedimentary rocks; Jurassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex (Jurassic)
Jurassic mixed marine detrital and volcanic rocks of western Idaho.
Metavolcanic and metasedimentary rocks; Middle to Lower Triassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex (Middle and Early Triassic)
Middle and Lower Triassic metabasalt and submarine volcaniclastics of western Idaho
Quartzite, argillite, carbonate, meta-conglomerate, siltite, intermediate volcanic rock; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic)
Younger Precambrian detrital units of central and southeastern Idaho; subdivisions are (Z2s and Z1s).
Quartzite, marble, Calc-silicate rock, schist, and meta-conglomerate; Ordovician to Middle Proterozoic metasedimentary rocks; central Idaho, Pioneer Mountains metamorphic core complex (Ordovician to Middle Proterozoic)
Ordovician to Middle Proterozoic metasedimentary rocks, undivided
Quartzite, siltstone, conglomerate, and metavolcanic rocks; Late and Middle Proterozoic, undivided; Atlanta batholith roof pendants (Late and Middle Proterozoic, undivided)
Precambrian, high-grade metamorphic rock
Rhyolitic tuffs, ignimbrites, and flows, basaltic flows, conglomerate and marlstone; Pliocene to Miocene volcano-sedimentary deposits; eastern Snake River Plain and southeastern Idaho (Pliocene-Miocene)
Pliocene volcanic units, generally air-fall or pyroclastic in origin; grade into (Tpd).
Sandstone, conglomerate, siltstone, tuff, claystone, limestone, and diatomite; Pliocene tuffaceous alluvial and lacustrine deposits; Snake River Plain and vicinity, southeastern Idaho (Pliocene )
Pliocene stream and lake deposits; may be due to volcanic and block-faulting events.
Sandstone, limestone, siltstone, shale, and conglomerate; Lower Permian to Middle Pennsylvanian deltaic turbidites; central Idaho; (Early Permian)
Lower Permian to Middle Pennsylvanian thrusted, marine detritus of central Idaho.
Shale, arenite, conglomerate, intermediate and felsic volcanic rocks; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic)
Younger Precambrian volcanic and diamictic units of central and southeastern Idaho.
Shale, conglomerate, sandstone, siltstone, limestone, and chert; Mississippian turbidite flysch from a western source; central Idaho (Mississippian)
Mississippian thrusted, shallow-to-deep marine detrital units of central Idaho.
Shale, limestone, and sandstone; Triassic marine to non-marine epicontinental deposits (subunits are TRl and TRu) (Triassic)
Triassic shallow-marine to non-marine sediments of eastern Idaho; subdivisions are (TRu and TRl).
Tuffaceous shale, sandstone, conglomerate, and lignite; Eocene to Pliocene alluvial and lacustrine deposits; central and southern Idaho (Tertiary)
Tertiary continental sediments; predominantly Upper Tertiary in age; subdivisions are:(Tpd, Tmd, and Ted).
Tuff, arkose, claystone, siltstone, conglomerate, lignite; Miocene alluvial and lacustrine deposits (Miocene)
Miocene stream and lake deposits; generally associated with volcanic episodes.
Kansas
Douglas Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Virgilian])
Lawrence FM (base LA)- mostly gray shale and sandstone with minor red shale, coal, gray limestone and conglomerate, thickness ranges from 140ft to 250 ft. Stranger FM- five members containing sandstone, shale, and minor limestone, coal and conglomerate ranging from 100 ft. to 180 ft. thickness.
Kiowa Shale and Cheyenne Sandstone (Phanerozoic | Mesozoic | Cretaceous-Early)
Kiowa Shale or FM- light -gray to black illitic shale with thin coquinoidal limestone beds at the base; sandstone lenses common. Cheyenne Sandstone- massive to crossbedded, light-gray to buff fine-grained sandstone with lenses of gray sandy shale and conglomerate.
Kentucky
Breathitt Formation, lower part (Pennsylvanian)
Breathitt Formation, lower part; lower part which includes Livingston Conglomerate Member of Lee Formation in eastern Rockcastle County
Caseyville Formation (Lower to Middle Pennsylvanian)
Caseyville Formation
Corbin Sandstone Member of Lee Formation (Pennsylvanian)
Corbin Sandstone Member of Lee Formation
Lee Formation (Mississippian to Pennsylvanian )
Lee Formation
Pennington Formation, Newman Limestone, Fort Payne Chert, Grainger Formation, Sunbury Shale, Berea Sandstone, and Bedford Shale, undivided; Pennington Formation locally includes sandstone tongue of Lee Formation (Devonian to Pennsylvanian)
Pennington Formation, Newman Limestone, Fort Payne Chert, Grainger Formation, Sunbury Shale, Berea Sandstone, and Bedford Shale, undivided; Pennington Formation locally includes sandstone tongue of Lee Formation
Rockcastle Sandstone Member of Lee Formation (Pennsylvanian)
Rockcastle Sandstone Member of Lee Formation
Tuscaloosa Formation (Upper Cretaceous)
Tuscaloosa Formation
Massachusetts
Ammonoosuc Volcanics (Middle Ordovician)
Ammonoosuc Volcanics - Basal quartzite and conglomerate.
Bellingham Conglomerate (Pennsylvanian, Cambrian or Proterozoic Z)
Bellingham Conglomerate - Red and gray metamorphosed conglomerate, sandstone, graywacke, and shale. Bellingham Conglomerate consists of conglomerate and lithic graywacke interbedded with chlorite phyllite and is confined to Bellingham basin. Also contains some volcanic rocks (rhyolite porphyry in roadcut on MA Hwy 146 at Premisy Hill west of Woonsocket, and felsite porphyry in the Franklin area east of Bellingham). Conglomerate contains pebbles of quartzite from adjacent Blackstone Group rocks and typical blue quartz of Milford Granite, so sediments are locally derived. Exposures on east side of Woonsocket Hill, southeast of Woonsocket, RI, show cliffs of steeply dipping, thin-bedded, white to gray quartzite of Blackstone Group standing above green schistose conglomerate containing many flattened white to gray quartzite pebbles and interbedded green calcareous quartz schist. Contact is probably a fault, but source of pebbles is quite obvious. In the same area, schist of Blackstone Group is difficult to distinguish from those of the Bellingham because of low-grade metamorphism of Blackstone rocks; it is probable that some of the low-grade Blackstone Rocks mapped northwest of Woonsocket in Blackstone River valley are part of Bellingham. The two rock units have been traditionally distinguished in the past by presence or absence of epidote (Warren and Powers, 1914), but this needs further study. Age is uncertain. Rocks have customarily been correlated with those of Pennsylvanian Narragansett basin; however, rocks in some exposures, such as the one at River St and Blackstone St in Woonsocket resemble Proterozoic Z Roxbury Conglomerate in Boston basin. Skehan and others (1979) suggest that Bellingham may have a similar age to that of Roxbury. This is supported by observation that Bellingham is a structural trough extending southwest from Boston basin and separating primarily Proterozoic Z granitoids from altered, but nongneissic, Proterozoic granitoids (Wones and Goldsmith, 1991). In deference to tradition, and because Proterozoic Z age has not been proven, age is shown on MA State bedrock map of Zen and others as Proterozoic Z to Pennsylvanian [map actually has age of Proterozoic Z, Cambrian, or Pennsylvanian, which differs from age stated in this report.] (Goldsmith, 1991).
Cambridge Argillite (Proterozoic Z to earliest Paleozoic)
Cambridge Argillite - Gray argillite and minor quartzite; rare sandstone and conglomerate. Contains acritarchs. Cambridge Argillite of Boston Bay Group contains sandy horizons which are in some places quartzite. Most prominent are Milton quartzite unit of Billings (1976), and Tufts Quartzite Member (described by Billings, 1929, and LaForge, 1932) in northern part of basin. Red sandstone and sandy argillite in Chelsea, Revere, and Milton-Quincy areas intertongue with green argillite (Kaye, 1980). Red beds lie above cleaner quartzites such as Tufts and Milton units. Core analysis by D.A. Ashenden (Metropolitan District Commission, 1980, written commun.) indicates that Cambridge and Braintree Argillites are identical. Age of Boston Bay rocks has been controversial and was once thought to be Cambrian to Pennsylvanian (the latter based on lithologic similarity to rocks of Narragansett basin and now discredited plant fossils). Age of Cambridge and of Boston Bay Group as a whole is Proterozoic Z and possibly Early Cambrian based on presence of acritarchs in Cambridge. Acritarchs are diagnostic species that ranges in age from Proterozoic Z to Early Cambrian, but is most abundant in Proterozoic Z time (Lenk and others, 1982; [also see Goldsmith and others, 1982]). Age is also supported by the following: 1) plant fossils so numerous in strata of Narragansett basin are absent in the Boston Bay Group strata, 2) Late Ordovician and Early Silurian Quincy Granite contains argillite inclusions that are on strike with Cambridge Argillite, and 3) Boston Bay Group stratigraphy is primarily marine, not similar to terrestrial stratigraphy of Narragansett basin (Goldsmith, 1991).
Clough Quartzite (Upper Silurian)
Clough Quartzite - Quartz-pebble conglomerate, quartzite, and minor mica schist and calc-silicate rocks. Fossils at Bernardston are similar to those at Croyden Mountain, New Hampshire which indicate late Llandoverian age. Parts of the Littleton and Partridge Formations, and Clough Quartzite in MA are here reassigned to the Rangeley Formation [here geographically extended to MA]. The four mapped areas of Clough Quartzite in the Amherst area west of the Connecticut Valley border fault are now interpreted as conglomerate lenses in the Rangeley. Clough is considered the key stratigraphic unit in Bronson Hill anticlinorium because 1) it is dominated by distinctive, readily recognizable rock types, 2) where present, it is base of Silurian-Devonian sequence, resting with detectable unconformity on older rocks, and 3) it contains late Llandoverian fossils at several localities in western NH and adjacent VT, and at Bernardston, MA. Consists mostly of quartz-pebble conglomerate in which pebbles are typically deformed; other lithologies are quartz grit or white to pink, well-bedded quartzite. Locally contains some mica schist beds. On the MA State bedrock geologic map (Zen and others, 1983), thickness is locally exaggerated because at many localities, the unit was only a few meters or less thick and could not be shown at a scale of 1:250,000. Maximum thickness is 200 m on west limb of Northfield syncline. Unconformably overlies Fourmile Gneiss in Pelham dome and in Kempfield anticline, or Ammonoosuc Volcanics over most gneiss domes. Partridge Formation occurs along Clough-Ammonoosuc contact as lenses in many areas (Hatch and others, 1988).
Coal Mine Brook Formation (Middle Pennsylvanian)
Coal Mine Brook Formation - Fossiliferous, carbonaceous slate and garnet phyllite with a lens of meta-anthracite; conglomerate and arkose.
Dalton Formation (Lower Cambrian and Proterozoic Z)
Dalton Formation - Tan to orangish-tan quartz and gneiss cobble and pebble conglomerate, rusty feldspathic schist, and lustrous greenish-gray muscovite quartz schist.
Dalton Formation (Lower Cambrian and Proterozoic Z)
Dalton Formation - Orangish-gray, gray, and light-greenish-gray muscovite-quartz schist and interlayered feldspathic quartzite and quartz conglomerate; minor beds of rusty albitic schist.
Dighton Conglomerate (Upper Pennsylvanian)
Dighton Conglomerate - Coarse conglomerate having sandy matrix; minor sandstone. Dighton Conglomerate occurs in Narragansett basin. Consists of gray conglomerate composed mainly of rounded quartzite cobbles to boulders containing subordinate rounded granite cobbles and slate pebbles; very little sand matrix; lenses of medium-grained sandstone form less than 20 percent of unit. Age is Pennsylvanian (Goldsmith, 1991).
East Berlin Formation (Lower Jurassic)
East Berlin Formation - Pale red conglomerate and arkosic sandstone. Assigned to Newark Supergroup (Robinson and Luttrell, 1985).
Greylock Schist (Lower Cambrian and Proterozoic Z)
Greylock Schist - Light-green to gray, white albite-spotted phyllite and interbedded blue-quartz metagraywacke, salmon-pink dolostone, and blue-quartz conglomerate. Minor interbeds of black and white albite-spotted phyllite resembles Hoosac (CAZhga).
Harvard Conglomerate (Pennsylvanian)
Harvard Conglomerate - Conglomerate and chloritoid-hematite phyllite.
Hoosac Formation (Lower Cambrian and Proterozoic Z)
Hoosac Formation - Light-gray, albite-biotite granofels and schist, pseudoconglomerate and blue quartz pebble conglomerate.
Hoosac Formation (Lower Cambrian and Proterozoic Z)
Hoosac Formation - Gray conglomerate containing pebbles of albite and blue quartz, and boulders of gneiss.
Mount Toby Formation (Lower Jurassic)
Mount Toby Formation - Pale red conglomerate and arkosic sandstone, coarsens eastward. The Mount Toby Conglomerate is here revised and renamed the Mount Toby Formation of the Newark Supergroup. It includes only the sedimentary strata in the Deerfield basin above the slump zone unconformity defined by Cornet (1977), or its projected equivalent at its contact with the underlying Turners Falls Sandstone. It includes conglomerates at the type locality, landslide deposits within the conglomerate, and sandstone and lake beds above the slump zone unconformity, which were formerly included in the Turners Falls Sandstone. Other rocks mapped as Mount Toby Conglomerate by Emerson (1898) in the Hartford, Deerfield, and Northfield basins have been assigned to the Portland, Sugarloaf, and Turners Falls Formations. Age is Sinemurian and Pliensbachian, based on the discovery by Cornet (1977) of palynoflora in these strata (Robinson and Luttrell, 1985).
Nassau Formation (Lower Cambrian and Proterozoic Z)
Nassau Formation - Rensselaer Graywacke Member - Greenish-gray, plagioclase-rich, blue quartz pebble metagraywacke and minor gneiss-cobble conglomerate.
New Haven Arkose (Lower Jurassic)
New Haven Arkose - Red, pink, and gray coarse-grained, locally conglomeratic arkose interbedded with brick-red shaley siltstone and fine-grained arkosic sandstone; boundary between Lower Jurassic (Jn) and Upper Triassic (TRn) parts is arbitrarily drawn through clastic rocks of similar lithology below gray mudstone containing Lower Jurassic palynofloral zone. Assigned to Newark Supergroup (Robinson and Luttrell, 1985).
Pondville Conglomerate (Lower Pennsylvanian)
Pondville Conglomerate - Quartz conglomerate having abundant sandy matrix; boulder conglomerate, arkose; fossil plants. Pondville Conglomerate is present in Narragansett and Norfolk basins. Although Chute (1964, 1966, 1969) recognized a lower boulder conglomerate member and an upper sandstone to pebble conglomerate member in the Pondville in the northeast part of the basin, such a division is not readily made to the southwest because of facies changes. Upper member grades into and interfingers with Wamsutta Formation. Basal beds nonconformably overlie Dedham Granite in northern part of Narragansett basin. Age of deposits in Narragansett and Norfolk basins ranges from Early to Late Pennsylvanian; however, Skehan and Murray (1980) assigned lower part of Pondville to Mississippian. Further study may reveal even older Paleozoic sediments in Narragansett basin (Goldsmith, 1991).
Portland Formation (Lower Jurassic)
Portland Formation - Reddish-brown to pale red conglomerate and arkose.
Red arkosic conglomerate, sandstone, and siltstone (Upper Triassic)
Red arkosic conglomerate, sandstone, and siltstone - In Essex County.
Rhode Island Formation (Upper and Middle Pennsylvanian)
Rhode Island Formation - Sandstone, graywacke, shale and conglomerate; minor beds of meta-anthracite. Fossil plants. Rhode Island Formation is thickest and most extensive formation in Narragansett basin. Does not extend to Norfolk basin. Consists of gray sandstone and siltstone and lesser amounts of gray to black shale, gray conglomerate, and coal beds 10 m thick. Interfingers with Wamsutta Formation in Narragansett basin. In places overlies Dedham Granite. Age is Middle and Late Pennsylvanian (Goldsmith, 1991).
Rhode Island Formation (Upper and Middle Pennsylvanian)
Rhode Island Formation - Conglomerate, sandstone, and graywacke. Rhode Island Formation is thickest and most extensive formation in Narragansett basin. Does not extend to Norfolk basin. Consists of gray sandstone and siltstone and lesser amounts of gray to black shale, gray conglomerate, and coal beds 10 m thick. Interfingers with Wamsutta Formation in Narragansett basin. In places overlies Dedham Granite. Age is Middle and Late Pennsylvanian (Goldsmith, 1991).
Roxbury Conglomerate (Proterozoic Z to earliest Paleozoic)
Roxbury Conglomerate - Conglomerate, sandstone, siltstone, argillite, and melaphyre. Consists of Brookline, Dorchester, and Squantum Members. Roxbury Conglomerate forms base of Boston Bay Group. Divided into Brookline, Dorchester, and Squantum Members. Conglomerate in Brookline Member contains clasts of Dedham Granite, quartzite (possibly from Westboro Formation), and volcanic rock from underlying Mattapan Volcanic Complex. Dorchester Member consists of interbedded argillite and sandstone and forms an intermediate unit between Brookline Member and overlying Cambridge Argillite. Uppermost Squantum Member is a distinctive diamictite which appears to pinch out in northern part of basin. Brighton Melaphyre lies within Brookline Member and consists of mafic volcanic rocks (quartz keratophyre, keratophyre, and spilite). Roxbury clearly lies nonconformably on Dedham Granite near Hull, MA; can be traced continuously over Mattapan Volcanic Complex. Age is Proterozoic Z and possibly Early Cambrian (Goldsmith, 1991).
Shuttle Meadow Formation (Lower Jurassic)
Shuttle Meadow Formation - Pale red conglomerate and arkosic sandstone. The Shuttle Meadow Formation is assigned to Newark Supergroup and is extended into MA in the Hartford basin. It consists of sandstone strata containing one interval of gray mudstone beds. The unit grades eastward along strike into a conglomeratic facies. It overlies the New Haven Arkose or Hitchcock Volcanics and underlies the Holyoke Basalt (Robinson and Luttrell, 1985).
Sugarloaf Formation (Lower Jurassic)
Sugarloaf Formation - Pale red conglomerate and arkosic sandstone, coarsens eastward.
Turner Falls Sandstone (Lower Jurassic)
Turner Falls Sandstone - Pale red conglomerate and arkosic sandstone.
Vaughn Hills Quartzite (Silurian or Ordovician)
Vaughn Hills Quartzite - Quartzite, phyllite, conglomerate, and chlorite schist.
Wamsutta Formation (Middle and Lower Pennsylvanian)
Wamsutta Formation - Red to pink, well-sorted conglomerate, graywacke, sandstone, and shale; fossil plants. Wamsutta Formation occurs in Narragansett and Norfolk basins. Consists of conglomerate, lithic graywacke, sandstone, and shale. Also contains rhyolite and basalt horizons near Attleboro. Northwest of Attleboro, Wamsutta overlies Diamond Hill Felsite as used by Skehan and Murray (in Skehan and others, 1979). Volcanic rocks similar to Diamond Hill Felsite crop out west of Lake Pearl, between Franklin and Wrentham, on west flank of Norfolk basin. These are shown within Wamsutta Formation on MA State bedrock map of Zen and others (1983) because of their proximity to Diamond Hill. They also resemble Proterozoic Z Mattapan Volcanic Complex. Chute (1966) described lenses of carbonate rock in red and green shale in Wamsutta in Norwood quad. Limestone also observed in rocks mapped as Wamsutta adjacent to exposed Dedham Granite at Manchester Pond Reservoir (J.P. Schafer, 1982, oral commun.). Red and green shales may actually be Cambrian. Upper member of Pondville Conglomerate grades into and interfingers with Wamsutta; in turn, Wamsutta interfingers with Rhode Island Formation in northwest part of Narragansett basin. Nonconformably overlies Dedham Granite. Partly equivalent to Rhode Island Formation. Age is Early and Middle Pennsylvanian. Contains a few plant fossils (Goldsmith, 1991).
Washington Gneiss (Proterozoic Y)
Washington Gneiss - Rusty-weathering, muscovite-biotite-sillimanite and/or kyanite-garnet schist; blue-quartz ribbed conglomerate, interlayered garnet-plagioclase-quartz metadacite.
Maryland
Chilhowee Group; Weverton Formation (Late Precambrian - Cambrian)
Weverton Formation - Interbedded white to dark gray, thin-bedded, micaceous, ferruginous, and sericitic quartzites, phyllites, and white, thick-bedded, ledge-making quartzites; some gray to brown ferruginous quartz conglomerate and purple-banded phyllite; thickness approximately 100 feet in south, increases to 425 feet in north.
Conococheague Limestone (Upper Cambrian to Lower Ordovician )
Conococheague Limestone - Dark blue, laminated, oolitic, argillaceaous, and siliceous limestone, algal limestone, and flat-pebble conglomerate; siliceous shale partings; some sandstone and dolomite; thickness 1,600 to 1,900 feet.
Juniata Formation (Ordovician)
Juniata Formation - Red to greenish-gray, thin- to thick-bedded siltstone, shale, subgraywacke, and protoquartzite; interbedded conglomerate; thickness 180 feet in east, increases to 500 feet in west.
New Oxford Formation (Triassic)
New Oxford Formation - Red, maroon, and gray sandstone, siltstone, and shale; basal conglomerate member: From vicinity of Maryland Rte. 73 and southward, limestone conglomerate with red and gray calcareous matrix; northward, quartz conglomerate with red sandy matrix; estimated total thickness 4,500 feet.
New Oxford Formation, basal limestone conglomerate (Triassic)
New Oxford Formation - basal conglomerate member: From vicinity of Maryland Rte. 73 and southward, limestone conglomerate with red and gray calcareous matrix
New Oxford Formation, basal quartz conglomerate (Triassic)
New Oxford Formation - basal conglomerate member: From vicinity of Maryland Rte. 73 northward, quartz conglomerate with red sandy matrix
Pocono Group, including the Purslane Sandstone and Rockwell Formation (Mississippian)
Pocono Group - Gray, white, tan, and brown, thin- to thick-bedded, cross-bedded sandstone, locally conglomeratic; interbedded gray and reddish-brown shale, mudstone, and siltstone; fragmentary plant fossils. Undifferentiated in Garrett and western Allegeny Counties. Includes Purslane Sandstone - White, thick-bedded, coarse-grained sandstone and conglomerate with thin coal beds and red shales. Eastern Allegany and Washington Counties. And also inlcudes Rockwell Formation - Coarse-grained arkosic sandstone, fine-grained conglomerate, and buff shale; dark shale with thin coal beds near base. Eastern Allegany and Washington Counties.
Maine
Carboniferous - Devonian unnamed conglomerate and sandstone (Carboniferous and/or Devonian)
Carboniferous - Devonian unnamed conglomerate and sandstone
Devonian Hobbstown Formation (Devonian)
Devonian Hobbstown Formation
Devonian Mapleton Formation (Devonian)
Devonian Mapleton Formation
Devonian Perry Formation sandstone member (Devonian)
Devonian Perry Formation sandstone member
Devonian Seboomook Formation Day Mountain member conglomerate (Devonian)
Devonian Seboomook Formation Day Mountain member conglomerate
Devonian Seboomook Formation Temple Stream member (Silurian-Devonian)
Devonian Seboomook Formation Temple Stream member
Devonian Seboomook Formation unnamed conglomerate (Devonian)
Devonian Seboomook Formation unnamed conglomerate
Devonian - Silurian Bar Harbor Formation (Devonian - Silurian)
Devonian - Silurian Bar Harbor Formation
Devonian - Silurian Bell Brook Formation, conglomerate member (Devonian - Silurian)
Devonian - Silurian Bell Brook Formation, conglomerate member
Devonian - Silurian Daggett Ridge Formation (Devonian - Silurian)
Devonian - Silurian Daggett Ridge Formation
Devonian - Silurian Towow Formation conglomerate (Devonian - Silurian)
Devonian - Silurian Towow Formation conglomerate
Devonian - Silurian unnamed conglomerate (Devonian - Silurian)
Devonian - Silurian unnamed conglomerate
Devonian Trout Valley Formation (Devonian)
Devonian Trout Valley Formation
Devonian unnamed conglomerate (Devonian)
Devonian unnamed conglomerate
Devonian unnamed limestone conglomerate (Devonian)
Devonian unnamed limestone conglomerate
Devonian unnamed lithic sandstone and conglomerate (Devonian)
Devonian unnamed lithic sandstone and conglomerate
Megunticook Formation, Polymictic Conglomerate Member (Ordovician - Cambrian)
Megunticook Formation, Polymictic Conglomerate Member
Ordovician - Cambrian Mount Battie Formation (Ordovician - Cambrian)
Ordovician - Cambrian Mount Battie Formation
Ordovician Chase lake formation (Ordovician)
Ordovician Chase lake formation
Ordovician Chase lake Formation conglomerate member (Ordovician)
Ordovician Chase lake Formation conglomerate member
Ordovician Lobster Mountain volcanic complex (Ordovician)
Ordovician Lobster Mountain volcanic complex
Ordovician sandstone and pelite of the Depot Mountain sequence (Ordovician)
Ordovician sandstone and pelite of the Depot Mountain sequence
Ordovician Shin Brook Formation (Ordovician)
Ordovician Shin Brook Formation
Precambrian Z Rockport Formation (Precambrian)
Precambrian Z Rockport Formation
Precambrian Z rocks of Islesboro (Precambrian Z)
Precambrian Z rocks of Islesboro
Silurian Ames Knob formation (Silurian)
Silurian Ames Knob formation
Silurian Capens Formation (Silurian)
Silurian Capens Formation
Silurian Frenchville Formation (Silurian)
Silurian Frenchville Formation
Silurian Hardwood Mountain Formation (Silurian)
Silurian Hardwood Mountain Formation
Silurian Oak Bay formation (Silurian)
Silurian Oak Bay formation
Silurian - Ordovician Lobster Lake Formation (Silurian - Ordovician)
Silurian - Ordovician Lobster Lake Formation
Silurian - Ordovician Mars Hill Conglomerate (Silurian - Ordovician)
Silurian - Ordovician Mars Hill Conglomerate
Silurian - Ordovician unnamed conglomerate (Silurian - Ordovician)
Silurian - Ordovician unnamed conglomerate
Silurian Rangeley Formation "A""member (Silurian)
Silurian Rangeley Formation "A" member
Silurian Rangeley Formation "A" member lithic sandstone" (Silurian)
Silurian Rangeley Formation "A" member lithic sandstone
Silurian Rangeley Formation "B" member (Silurian)
Silurian Rangeley Formation "B" member"
Silurian Rangeley Formation "C" member (Silurian)
Silurian Rangeley Formation "C" member
Silurian Sangerville Formation (Silurian)
Silurian Sangerville Formation
Silurian Sangerville Formation conglomerate member (Silurian)
Silurian Sangerville Formation conglomerate member
Silurian undifferentiated conglomerates and coarse-grained sandstones (Silurian)
Silurian undifferentiated conglomerates and coarse-grained sandstones, in part of the Allsbury Formation and in part unnamed
Silurian undifferentiated pelites and sandstones (Silurian)
Silurian undifferentiated pelites and sandstones, in part of the Allsbury Formation and in part unnamed
Silurian unnamed conglomerate (Silurian)
Silurian unnamed conglomerate
Silurian unnamed conglomerate and sandstone (Silurian)
Silurian unnamed conglomerate and sandstone
Michigan
Baraga Group; Copps Formation (Early Proterozoic)
Baraga Group; Copps Formation - Fine- to medium-grained graywacke and less abundant gray to black slate. Thin basal conglomerate west of Lake Gogebic contains clasts of underlying Archean rocks in a quartzitic and argillaceous matrix.
Copper Harbor Conglomerate (Middle Proterozoic)
Copper Harbor Conglomerate - Red lithic conglomerate and sandstone; mafic to felsic volcanic flows similar to those of the unnamed formation (unit Yu) are interlayered with the sedimentary rocks.
Jacobsville Sandstone (Middle Proterozoic)
Jacobsville Sandstone - Red, brown, and white quartzose sandstone, and minor siltstone, shale and conglomerate
Menominee Group; Blair Creek Formation (Early Proterozoic)
Menominee Group; Blair Creek Formation - Dominantly dark-gray, massive, porphyritic tholeiitic basalt. Includes a basal conglomerate and a lean iron-formation in middle of formation
Munising Formation (Late Cambrian)
Munising Formation
Oronto Group; Freda Sandstone; Conglomerate member (Middle Proterozoic)
Oronto Group; Freda Sandstone; Conglomerate member
Minnesota
Animikie Group; Iron-formation - Iron-formation (Early Proterozoic)
Animikie Group; Iron-formation - Includes the Gunflint Iron Formation in Cook County and the Biwabik Iron Formation and subjacent units of arenite and conglomerate assigned to the Pokegama Quartzite in Itasca, St. Louis, and Lake Counties. Also includes thin lenses of iron-formation (Remer Member) in the Virginia Formation in Itasca County.
Coleraine Formation (Cretaceous)
Coleraine Formation - Jasper-pebble conglomerate, sandstone, and shale of diverse origin on the Mesabi range of northern Minnesota, and unnamed sandstone and shale of nonmarine to marine origin in east-central Minnesota
Fond du Lac Formation (Middle Proterozoic)
Fond du Lac Formation - Red to dark-brown shale, feldspathic sandstone, and arkose of fluvial origin. Includes the Oldenberg Point Member, a pronounced basal unit of quartz-pebble conglomerate in the Duluth area.
Sioux Quartzite (Early Proterozoic)
Sioux Quartzite - Red quartzite of fluvial to possibly marginally marine origin. Includes quartz-pebble conglomerate, claystone (catlinite, also called pipestone), a basal (rhyolite) pebble conglomerate in Pipestone County, and a basal (granite, quartz, chert, iron-formation) conglomerate in Nicollet County on the Minnesota River
Missouri
ELVINS GROUP- (INCLUDING DERBY-DOERUN DOLOMITE, DAVIS FORMATION), BONNETERRE DOLOMITE (Phanerozoic | Paleozoic | Cambrian-Furongian [Croixian])
ELVINS GROUP - (INCLUDING DERBY - DOERUN DOLOMITE - alternating thin dolomite, siltstone, and shale; DAVIS FORMATION - glauconitic shale with fine - grained sandstone, limestone, and dolomite); BONNETERRE DOLOMITE - dolomite, dolomitic limestone, and limestone; glauconitic in lower part
SMITHVILLE DOLOMITE, POWELL DOLOMITE, COTTER DOLOMITE, JEFFERSON CITY DOLOMITE (Phanerozoic | Paleozoic | Ordovician-Early [Ibexian])
SMITHVILLE DOLOMITE, POWELL DOLOMITE, COTTER DOLOMITE, JEFFERSON CITY DOLOMITE - fine crystalline, silty, cherty dolomite, and oolitic chert with local sandstone beds
Montana
Arikaree formation (Phanerozoic | Cenozoic | Tertiary)
Arikaree formation: gray sandstone with layers of concretions; contains volcanic ash and, locally, channels filled with conglomerate; known only in southeastern Montana.
Cambrian, undifferentiated (Phanerozoic | Paleozoic | Cambrian)
Cambrian, undifferentiated: comprises Deadwood formation, in south-central Montana, and Red Lion formation, Dry Creek shale, Hasmark formation, Pilgrim limestone, Silver Hill formation, Park shale, Meagher limestone, Wolsey shale, Flathead quartzite, and other units. In a few places quartzite of Cambrian age may be mapped with the Belt series or quartzite of Belt age with the Cambrian rocks.
Devonian, undifferentiated (Phanerozoic | Paleozoic | Devonian)
Devonian, undifferentiated: comprises Three Forks formation consisting of carbonaceous and calcareous shale with some sandstone and limestone, Jefferson limestone, and unnamed units of Devonian age.
Grinnell argillite (Proterozoic | Mesoproterozoic)
Grinnell argillite: reddish-purple and green argillite, quartzitic argillite, and some quartzite; generally contains some feldspar and carbonates.
Horsethief sandstone (Phanerozoic | Mesozoic | Cretaceous-Late)
Horsethief sandstone: shaly sandstone grading upward into massive brownish cliff-forming sandstone with local concentrations of magnetite in beds near top.
Missoula group (Proterozoic | Mesoproterozoic)
Missoula group: chiefly red, maroon, or purple argillite; sandy or quartzitic argillite, and generally impure quartzite and limestone. The larger limestone masses are similar to the Siyeh limestone of the Piegan group. The Missoula group includes numerous named formations, most of which cannot be traced with confidence far from their type localities. Among these are the Marsh shale in the Helena region, the Striped Peak and Libby formations in northwestern Montana, five near Missoula, and others in and south of Glacier National Park.
Missoula group (Proterozoic | Mesoproterozoic)
Missoula group: chiefly red, maroon, or purple argillite; sandy or quartzitic argillite, and generally impure quartzite and limestone. The larger limestone masses are similar to the Siyeh limestone of the Piegan group. The Missoula group includes numerous named formations, most of which cannot be traced with confidence far from their type localities. Among these are the Marsh shale in the Helena region, the Striped Peak and Libby formations in northwestern Montana, five near Missoula, and others in and south of Glacier National Park.
Paleozoic rocks, undifferentiated (Phanerozoic | Paleozoic)
Paleozoic rocks, undifferentiated: in east-central Madison County where scale did not permit differentiation on map.
Pennsylvanian, undifferentiated (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian)
Pennsylvanian, undifferentiated: in western Montana is mainly the Quadrant quartzite but includes limestone and other rocks of Pennsylvanian age so far as present data permit. Farther east other formations of Pennsylvanian or possible Pennsylvanian age are included.
Willow Creek formation (Phanerozoic | Cenozoic | Cretaceous-Late)
Willow Creek formation: Variegated clay and soft sandstone, chiefly maroon to chocolate brown; local lenses of purple-gray nodular limestone.
North Carolina
Alligator Back Formation; Gneiss (Late Proterozoic)
Gneiss - finely laminated to thin layered; locally contains massive gneiss and micaceous granule conglomerate; includes schist, phyllite, and amphibolite.
Beaufort Formation, Undivided (Tertiary)
Beaufort Formation, Undivided - Unnamed upper member: sand and silty clay, glauconitic, fossiliferous, and locally calcareous. Jericho Run Member: siliceous mudstone with sandstone lenses, thin bedded; basal phosphatic pebble conglomerate.
Castle Hayne Formation; Comfort Member and New Hanover Member, undivided (Tertiary)
Comfort Member and New Hanover Member, undivided - Comfort Member: bryozoan-echinoid skeletal limestone, locally dolomitized, solution cavities common. New Hanover Member: phosphate-pebble conglomerate, micritic, thin; restricted to basal part of Castle Hayne Formation in southeastern counties.
Chilhowee Group; Lower Chilhowee (Cambrian)
Lower Chilhowee - feldspathic arenite, white to yellowish gray. Minor silty shale, feldspathic siltstone, and conglomerate in lower part. Includes Unicoi Formation of Hot Springs window.
Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic)
Metamudstone and Meta-Argillite - bedding plane and axial-planar cleavage common; interbedded with metasandstone, meta-conglomerate, and metavolcanic rock.
Newark Supergroup, Chatham Group; Chatham Group, Undivided (Triassic)
Chatham Group, Undivided - conglomerate, fanglomerate, sandstone, and mudstone. Conglomerate and fanglomerate shown by pattern.
Newark Supergroup, Chatham Group; Pekin Formation (Triassic)
Pekin Formation - conglomerate, sandstone, and mudstone.
Newark Supergroup, Chatham Group; Sanford Formation (Triassic)
Sanford Formation - conglomerate, fanglomerate, sandstone, and mudstone.
Newark Supergroup, Dan River Group; Dan River Group, Undivided (Triassic)
Dan River Group, Undivided - basin-margin conglomerate and sandstone, red to brown, interfingering with basin-center sandstone and mudstone, green to brown. Conglomerate shown by pattern.
Newark Supergroup, Dan River Group; Pine Hall Formation (Triassic)
Pine Hall Formation - sandstone, mudstone, and conglomerate, yellowish orange to brown.
Newark Supergroup, Dan River Group; Stoneville Formation (Triassic)
Stoneville Formation - conglomerate, sandstone, and mudstone, lenticular and laterally-gradational bedding.
Ocoee Supergroup, Snowbird Group, undivided (Late Proterozoic)
Snowbird Group, undivided - feldspathic metasiltstone, metasandstone, and phyllite. Basal schist contains lenses of quartz-pebble conglomerate.
Nebraska
Arikaree Group (Phanerozoic | Cenozoic | Tertiary | Oligocene Miocene)
Consists mainly of gray, fine, loose to compact sand that has layers of hard, fine-grained dark-gray concretions which vary from few in to 15 in and often have tabular form. Includes a large amount of volcanic ash mixed in with the sand. Contains a number of channels filled with coarse conglomerate along ridge south of North Platte River. About 500 ft thick.
New Hampshire
Fitch and Clough Formations, undivided (Silurian)
Fitch and Clough Formations, undivided.
Member C (uppermost) of the Rangeley Formation in Maine and northeastern and southwestern New Hampshire (Lower Silurian (Llandoverian))
Member C (uppermost) of the Rangeley Formation in Maine and northeastern and southwestern New Hampshire - Quartz-pebble conglomerate overlain by rusty metapelite and feldspathic quartzite.
Perry Mountain and Rangeley Formations, undivided (Silurian)
Perry Mountain and Rangeley Formations, undivided.
New Jersey
Basalt-clast Conglomerate (Lower Jurassic)
Basalt-clast Conglomerate - Dark to very-dark-gray conglomerate with clasts mostly of sub-angular to subrounded greenish-black basalt cobbles and boulders. Other clasts (about 10 to 15%) are pebbles to boulders of hornblende granite with pink feldspar. Matrix is dark-pinkish-gray arkosic sand. Locally onlaps the Hook Mountain Basalt along the Ramapo Fault in northeast part of map area. Maximum thickness of unit unknown.
Berkshire Valley and Poxono Island Formations, undivided (Upper Silurian)
Berkshire Valley and Poxono Island Formations, undivided - Thickness ranges from 76 m (250 ft) at Greenwood Lake to 122 m (400 ft) in Longwood Valley. Berkshire Valley Formation (Barnett, 1970) - Commonly yellowish-gray weathering, medium-gray to pinkish-gray, very thin to thin-bedded fossiliferous limestone interbedded with gray to greenish-gray calcareous siltstone and silty dolomite, medium-gray to light-gray dolomite conglomerate, and grayish-black, thinly laminated shale. Lower contact conformable. Thickness ranges from 27 to 38 m (90-125 ft) thick. Poxono Island Formation, (White, 1882; Barnett, 1970) - Very thin to medium-bedded sequence of medium-gray, greenish-gray, or yellowish-gray, mud-cracked dolomite; light-green, pitted, medium-grained calcareous sandstone, siltstone, and edgewise conglomerate containing gray dolomite; and quartz-pebble conglomerate containing angular to subangular pebbles as much as 2 cm (0.8 in.) long. Interbedded grayish-green shales at lower contact are transitional into underlying Longwood Shale. Thickness ranges from 49 to 84 m (160-275 ft) thick.
Bloomsburg Red Beds (Upper Silurian)
Bloomsburg Red Beds (White, 1883) (High Falls Shale of previous usage) - Grayish-red, thin- to thick-bedded, poorly to moderately well sorted, massive siltstone, sandstone, and local quartz-pebble conglomerate containing local planar to trough crossbedded laminations. Conglomerate consists of matrix-supported quartz pebbles in grayish-red, fine-grained sandstone matrix. Locally, near base of unit, is greenish-gray, light-gray, or grayish-orange, massive, planar tabular to trough crossbedded quartz sandstone to siltstone with subrounded grains. Lower part of formation marked by several upward-fining sequences of light-gray sandstone grading through grayish-red, fine-grained sandstone and siltstone to grayish-red, mudcracked siltstone and mudstone. Each sequence is 1 to 3 m (3-10 ft) thick. Lower contact placed at bottom of lowermost red sandstone. Thickness approximately 460 m (1,510 ft).
Boonton Formation (Lower Jurassic)
Boonton Formation (Olsen, 1980) - Reddish-brown to brownish-purple, fine-grained sandstone, siltstone, and mudstone; sandstone commonly micaceous, interbedded with siltstone and mudstone in fining-upward sequences mostly 1.5 to 4 m (5-13 ft) thick. Red, gray and brownish-purple siltstone and black, blocky, partly dolomitic siltstone and shale common in lower part. Irregular mudcracks, symmetrical ripple marks, and burrows, as well as gypsum, glauberite, and halite pseudomorphs are abundant in red mudstone and siltstone. Gray, fine-grained sandstone may have carbonized plant remains and reptile footprints in middle and upper parts of unit. Near Morristown, beds of quartz-pebble conglomerate (unit Jbcq) as much as 0.5 m (1.6 ft) thick interfinger with beds of sandstone, siltstone, and shale. Northeast of Boonton, beds of quartz-pebble conglomerate (not mapped separately as Jbcq) occur locally with conglomerate containing abundant clasts of gneiss and granite in matrix of reddish-brown sandstone and siltstone. Maximum thickness is about 500 m (1,640 ft).
Chestnut Hill Formation (Late Proterozoic)
Chestnut Hill Formation (Drake, 1984) - Interbedded arkose, ferruginous quartzite, quartzite conglomerate, metarhyolite, and metasaprolite. Confined to a few small areas north and east of Phillipsburg, on the western side of Bowling Green Mountain, northwest of High Bridge, and a few areas too small to show at this map scale.
Feltville Formation Conglomerate and Sandstone facies (Lower Jurassic)
Feltville Formation Conglomerate and Sandstone facies - Near Oakland, subrounded pebbles to cobbles of quartzite and quartz in a red siltstone and sandstone matrix (Jfc) interfinger with sandstone and siltstone of the Feltville Formation.
Green Pond Conglomerate (Lower (?) and Middle Silurian)
Green Pond Conglomerate (Rogers, 1836) - Medium- to coarse-grained quartz-pebble conglomerate, quartzitic arkose and orthoquartzite, and thin- to thick-bedded reddish-brown siltstone. Grades downward into gray, very dark-red, or grayish-purple, medium- to coarse-grained, thin- to very thick bedded pebble to cobble conglomerate containing clasts of red shale, siltstone, and chert; yellowish-gray sandstone and chert; dark-gray shale and chert; and white-gray and pink milky quartz. Quartz cobbles are as long as 10 cm (4 in.), and rare red shale clasts as much as 46 cm (18 in.) across. Milky quartz pebbles average 2.5 cm (1 in.) in length. Red arkosic quartz-pebble conglomerate and quartzite are more abundant than gray and grayish-green quartzite. Unconformably overlies Martinsburg Formation, Allentown Dolomite, Leithsville Formation, or Proterozoic rocks. About 305 m (1000 ft) thick.
Hardyston Quartzite (Lower Cambrian)
Hardyston Quartzite (Wolff and Brooks, 1898) - Medium- to light-gray, fine- to coarse-grained, medium- to thick-bedded quartzite, arkosic sandstone and dolomitic sandstone. Basal pebble to cobble conglomerate typically contains clasts of local basement affinities. Contains fragments of the trilobite Olenellus thompsoni of Early Cambrian age. Thickness approximately 0.5 to 62 m (1.6-200 ft).
Hardyston Quartzite (Lower Cambrian)
Hardyston Quartzite (Lower Cambrian) (Wolff and Brooks, 1898) - Light- to medium-gray and bluish-gray conglomeratic sandstone. Varies from pebble conglomerate, to fine-grained, well-cemented quartzite, to arkosic or dolomitic sandstone. Conglomerate contains subangular to subrounded white quartz pebbles up to 2.5 cm (1 in.). Lower contact unconformable. About 0 to 9 m (1-30 ft) thick.
Jacksonburg Limestone (Middle Ordovician)
Jacksonburg Limestone (Kummel, 1908; Miller, 1937) - Upper part is medium- to dark-gray, laminated to thin-bedded shaly limestone and less abundant medium-gray arenaceous limestone containing quartz-sand lenses. Upper part thin to absent to northeast. Lower part is interbedded medium- to dark-gray, fine- to medium-grained, very thin to medium-bedded fossiliferous limestone and minor medium- to thick-bedded dolomite-cobble conglomerate having a limestone matrix. Unconformable on Beekmantown Group and conformable on the discontinuous sequence at Wantage in the Paulins Kill area. Contains conodonts of North American midcontinent province from Phragmodus undatus to Aphelognathus shatzeri zones of Sweet and Bergstrom (1986). Thickness ranges from 41 to 244m (135-800 ft).
Jacksonburg Limestone and Sequence at Wantage, undivided (Middle Ordovician)
Jacksonburg Limestone and Sequence at Wantage, undivided - Jacksonburg Limestone - Upper part is medium- to dark-gray, laminated to thin-bedded shaly limestone and less abundant medium-gray arenaceous limestone containing quartz-sand lenses. Upper part thin to absent to northeast. Lower part is interbedded medium- to dark-gray, fine- to medium-grained, very thin to medium-bedded fossiliferous limestone and minor medium- to thick-bedded dolomite-cobble conglomerate having a limestone matrix. Unconformable on Beekmantown Group and conformable on the discontinuous sequence at Wantage in the Paulins Kill area. Contains conodonts of North American midcontinent province from Phragmodus undatus to Aphelognathus shatzeri zones of Sweet and Bergstrom (1986). Thickness ranges from 41 to 244m (135-800 ft). Sequence at Wantage - Restricted, discontinuous sequence of interbedded limestone, dolomite, conglomerate, siltstone, and shale. Upper part is medium-yellowish-brown- to olive-gray-weathering, medium- to dark-gray, very fine to fine-grained, laminated to massive limestone and dolomite that grade down into underlying clastic rocks of lower part. Upper part locally absent. Lower part ranges from grayish-red, medium-gray, pale-brown, and greenish-gray to pale-green mudstone and siltstone containing disseminated subangular to subrounded chert-gravel, quartz-sand lenses, and chert-pebble conglomerate. Lower contact unconformable. Thickness ranges from 0 to 46 m (0-150 ft).
Jutland Klippe Sequence, undifferentiated (Middle Ordovician to Upper Cambrian?)
Jutland Klippe Sequence, undifferentiated - Rocks of the Jutland klippe sequence occur in six isolated fragments of the Jutland klippe east of Jutland and two fragments of the Peapack klippe along the Peapack-Ralston fault in the New Jersey Highlands hinterland. The sequence is largely varicolored shale and sandstone, but contains lesser amounts of limestone, dolomite and pebble conglomerate. Lash and Drake (1984) correlate this sequence with the accretionary prism deposits of the Greenwich slice of the Hamburg klippe in eastern Pennsylvania. Rocks of the Jutland klippe sequence were folded and thrust over rocks of the Kittatinny Valley sequence during the Taconic orogeny and then were deformed during the Alleghanian orogeny and again during Mesozoic rifting of eastern North America.
Jutland Klippe Sequence Unit A (lower Middle Ordovician to Upper Cambrian)
Jutland Klippe Sequence Unit A of Perissoratis and others (1979) - Interbedded red, green, and tan shale, sandstone, and dark-gray, aphanitic to fine-grained limestone, which contains floating quartz-sand grains. Grades downward through interbedded sequence of red, green and brown shale to medium-gray to brown, fine- to coarse-grained sandstone and quartz-pebble conglomerate. Lower beds are dark-gray shale and siltstone containing minor dark-gray, aphanitic to fine-grained, medium-bedded limestone. Lower contact is a fault. Contains graptolites in the span of Anisograptus to Isograptus caduceus of Berry (1968) (Perissoratis and others, 1979) and conodonts of the Cordylodus proavus to Paroistodus proteus faunas of the North Atlantic Realm. Thickness is unknown.
Kanouse and Esopus Formations and Connelly Conglomerate, undivided (Lower Devonian)
Kanouse and Esopus Formations and Connelly Conglomerate, undivided - Kanouse Sandstone (Kummel, 1908) - Medium-gray, light-brown, and grayish-red, fine- to coarse-grained, thin- to thick-bedded sparsely fossiliferous sandstone and pebble conglomerate. Basal conglomerate beds are interbedded with siltstone similar to the upper part of the Esopus Formation and contain well-sorted, subangular to subrounded, gray and white quartz pebbles less than 1 cm (0.4 in.) long. Lower contact gradational. About 14 m (46 ft) thick. Esopus Formation - (Vanuxem, 1842; Boucot, 1959) - Light- to dark-gray, laminated to thin-bedded siltstone interbedded with dark-gray to black mudstone, dusky-blue sandstone and siltstone, and yellowish-gray fossiliferous siltstone and sandstone. Lower contact probably conformable with the Connelly Conglomerate. The formation is about 100 m (330 ft) thick at Greenwood Lake and estimated at 55 m (180 ft) thick in Longwood Valley. Connelly Conglomerate (Chadwick, 1908) - Grayish-orange weathering, very light gray to yellowish-gray, thin-bedded quartz-pebble conglomerate. Quartz pebbles average 1 to 2 cm (0.4-0.8 in.), are subrounded to well rounded, and well sorted. The unit unconformably overlies the Berkshire Valley Formation. About 11 m (36 ft) thick.
Lockatong Formation - Conglomerate facies (Upper Triassic)
Lockatong Formation Sandstone and Conglomerate Sandstone facies - Unit Trla interfingers laterally and gradationally with quartz sandstone and conglomerate (Trls) and quartzite conglomerate (Trlcq) near Triassic border fault in southwestern area of map.
Lockatong Formation - Sandstone and Conglomerate facies (Upper Triassic)
Sandstone and Conglomerate Sandstone facies - Unit Trla interfingers laterally and gradationally with quartz sandstone and conglomerate (Trls) and quartzite conglomerate (Trlcq) near Triassic border fault in southwestern area of map.
Oriskany Group, undivided (Lower Devonian)
Oriskany Group, undivided (Willard, 1938) - Thickness ranges from 38 m (125 ft) in southwest to 52 m (170 ft) in northeast. Ridgely Sandstone (Swartz and others, 1913) - White-weathering, medium-gray, medium- to thick-bedded, carbonate-cemented quartz-pebble conglomerate and coarse quartz sandstone, which contain abundant brachiopods. Moderately well sorted, subrounded sand gains. Unit thins northeastward and pinches out at Peters Valley. Lower contact abrupt. Thickness ranges from 0 to 10 m (0-32 ft). Shriver Chert (Swartz and others, 1913) - Medium- to dark-gray-weathering, black to dark-gray, medium-to-thick-bedded siltstone and shale containing interbedded black chert and local chert-bearing limestone. Present only in southwestern part of outcrop area where lower contact is gradational with silty limestone of Glenarie Formation. Thickness ranges from 0 to 9 m (0-30 ft). Glenarie Formation (Chadwick, 1908) - Medium-gray-weathering, medium- to dark-gray, fine-grained, thin- to medium-bedded, fossiliferous, silty limestone, and local chert lenses. Unit thickens to northeast. Lower contact probably gradational. Thickness ranges from 17 to 52 m (55-170 ft).
Passaic Formation Conglomerate and Sandstone facies (Lower Jurassic and Upper Triassic)
Passaic Formation Conglomerate and Sandstone facies - Conglomeratic sandstone (JTrpsc) is brownish-red pebble conglomerate, medium- to coarse-grained, feldspathic sandstone and micaceous siltstone; unit is planar to low-angle trough cross laminated, burrowed, and contains local pebble layers. Unit forms upward-fining sequences 0.5 to 2.5 m (1.6-8 ft) thick. Conglomeratic sandstone thickness exceeds 800 m (2,625 ft).
Passaic Formation Limestone-clast Conglomerate facies (Lower Jurassic and Upper Triassic)
Passaic Formation Limestone-clast Conglomerate facies - Limestone conglomerate unit (JTrpcl) is medium-bedded to massive, pebble to boulder conglomerate. Clasts are subangular dolomitic limestone in matrix of brownish- to purplish-red sandstone to mudstone; matrix weathers light-gray to white near faults. Maximum thickness unknown.
Passaic Formation Quatzite-clast Conglomerate facies (Lower Jurassic and Upper Triassic)
Passaic Formation Quartzite-clast Conglomerate facies - Quartzite conglomerate unit (JTrpcq) is reddish-brown pebble conglomerate, pebbly sandstone, and sandstone, in upward-fining sequences 1 to 2 m (3-6 ft) thick. Clasts are subangular to subrounded, quartz and quartzite in sandstone matrix. Sandstone is medium to coarse grained, feldspathic (up to 20 percent feldspar), and locally contains pebble and cobble layers. Conglomerate thickness exceeds 850 m (2,790 ft).
Quartz-pebble Conglomerate (Lower Jurassic)
Quartz-pebble Conglomerate - Reddish-brown to brownish-purple, fine-grained sandstone, siltstone, and mudstone; sandstone commonly micaceous, interbedded with siltstone and mudstone in fining-upward sequences mostly 1.5 to 4 m (5-13 ft) thick. Red, gray and brownish-purple siltstone and black, blocky, partly dolomitic siltstone and shale common in lower part. Irregular mudcracks, symmetrical ripple marks, and burrows, as well as gypsum, glauberite, and halite pseudomorphs are abundant in red mudstone and siltstone. Gray, fine-grained sandstone may have carbonized plant remains and reptile footprints in middle and upper parts of unit. Near Morristown, beds of quartz-pebble conglomerate (unit Jbcq) as much as 0.5 m (1.6 ft) thick interfinger with beds of sandstone, siltstone, and shale. Northeast of Boonton, beds of quartz-pebble conglomerate (not mapped separately as Jbcq) occur locally with conglomerate containing abundant clasts of gneiss and granite in matrix of reddish-brown sandstone and siltstone. Maximum thickness is about 500 m (1,640 ft).
Rondout and Decker Formations, undivided (Lower Devonian and Upper Silurian)
Rondout and Decker Formations, undivided - Rondout Formation (Clarke and Schuchert, 1899) - Upper part is medium-gray weathering, medium-dark-gray, very fine to fine-grained, medium-bedded, fossiliferous, argillaceous limestone. Middle part is light-medium-gray-weathering, medium-gray, laminated to medium-bedded, argillaceous dolomite. Locally contains deep desiccation polygons. Lower part is medium-gray-weathering, medium- to dark-gray, very fine to medium-grained, medium-bedded fossiliferous limestone. Silurian-Devonian boundary placed in middle of formation (Denkler and Harris, 1988). Lower contact abrupt and placed at top of highest calcareous quartz sandstone. Thickness approximately 12 m (40 ft). Decker Formation (White, 1882) - Light-gray- to yellowish-gray-weathering, light- to medium-gray, calcareous quartz siltstone, sandstone, and fine-pebble conglomerate locally interbedded with fossiliferous medium-gray, medium- to coarse-grained limestone and very fine grained, thin- to medium-bedded dolomite. Lower contact gradational. Thickness varies from 15 m (50 ft) near Duttonville to 25 m (82 ft) at Wallpack Center.
Shawangunk Formation (Middle and Lower Silurian)
Shawangunk Formation (Mather, 1840; Epstein and Epstein, 1972) - Upper part is medium- to medium-dark-gray, or dark-greenish-gray, medium- to thick-bedded sandstone and pebble conglomerate having well rounded grains, some of which are limonite stained. Conglomerate consists of matrix-supported quartz and subordinate shale pebbles as long as 5 cm (2 in.) in poorly to well-sorted, planar tabular to trough crossbedded sandstone. Local black to dark-greenish-gray, thin-bedded shale near upper contact. Middle part, occurring in southwest and sporadically in northeast, is light- to medium-dark-gray, greenish-gray, interbedded thin- to medium-bedded, planar tabular to trough cross-bedded shale and sandstone. Grains are well rounded and moderately to well sorted. Contains sparse graphite flakes. Lower part is light- to medium-gray to light-olive-gray, thin- to thick-bedded quartz and feldspathic sandstone, quartzite, and quartz-pebble conglomerate, which is matrix-supported, poorly to well sorted, cross to planar bedded. Clasts are primarily quartz and sparse dark-gray argillite and black chert. Sandstone is feldspathic and locally approaches an arkose in compostion. Lower contact unconformable and, at places, is a fault of small displacement. Thickness approximately 427 m (1,400 ft).
Skunnemunk Conglomerate (Middle Devonian)
Skunnemunk Conglomerate (Darton, 1894) - Grayish-purple to grayish-red, thin- to very thick bedded, locally cross-bedded, polymictic conglomerate and sandstone containing clasts of white vein quartz, red and green quartzite and sandstone, red and gray chert, and red shale; interbedded with medium-gray, thin-bedded sandstone and greenish-gray and grayish-red, mud-cracked shale. Conglomerate and sandstone matrix is primarily hematite and microcrystalline quartz. Conglomerate cobbles range to 16.5 cm (6.5 in) long, and average cobble size increases in upper part of unit. Lower contact conformable and gradational as defined by Kummel and Weller (1902). About 915 m (3,000 ft) thick.
Stockton Formation Cobble Conglomerate and Sandstone facies (Upper Triassic)
Stockton Formation Cobble Conglomerate and Sandstone facies - Unit is coarser near Newark basin border fault, where poorly exposed, reddish-brown to pinkish-white, medium- to coarse-grained, feldspathic pebbly sandstone and conglomerate (Trss) and pebble to cobble quartzite conglomerate (Trscq).
Stockton Formation Cobble Conglomerate and Sandstone facies (Upper Triassic)
Stockton Formation Cobble Conglomerate and Sandstone facies - Predominantly medium- to coarse-grained, light-gray, light-grayish-brown, or yellowish- to pinkish-gray arkosic sandstone and medium- to fine-grained, violet-gray to reddish-brown arkosic sandstone; with lesser, reddish to purplish-brown, silty mudstone, argillaceous siltstone, and shale. Some coarse-grained sandstone in lower part contains thick beds of conglomerate (Trsc) which have been mapped in the vicinity of Stockton. Sandstone, deposited in high-gradient stream channels, is mostly planar bedded with scoured bases containing pebble lags and mudstone rip-up clasts. Upper part of channel beds are burrowed. Large-scale trough crossbeds occur in some very coarse grained sandstone beds; smaller scale trough and climbing-ripple cross lamination occur in the upper part of channel sequences and in finer grained sandstone beds. Typical floodplain mudstones are irregularly thin bedded and extensively burrowed. Floodplain beds are thicker and more numerous in the central Newark basin, near the Delaware River. Thickness of the unit (including Trsc) near Stockton is about 1,240 m (4,068 ft).
Stockton Formation Cobble Conglomerate and Sandstone facies (Upper Triassic)
Stockton Formation Cobble Conglomerate and Sandstone facies - Unit is coarser near Newark basin border fault, where poorly exposed, reddish-brown to pinkish-white, medium- to coarse-grained, feldspathic pebbly sandstone and conglomerate (Trss) and pebble to cobble quartzite conglomerate (Trscq).
Towaco Formation (Lower Jurassic)
Towaco Formation (Olsen, 1980) - Reddish-brown to brownish-purple, fine- to medium-grained micaceous sandstone, siltstone, and silty mudstone in upward-fining sequences 1 to 3 m (3-10 ft) thick. Distributed throughout formation are eight or more sequences of gray to greenish- or brownish-gray, fine-grained sandstone, siltstone and calcareous siltstone and black, microlaminated calcareous siltstone and mudstone containing diagnostic pollen, fish and dinosaur tracks. Sandstone is commonly trough cross laminated; siltstone is commonly planar laminated or bioturbated, but can be indistinctly laminated to massive. Thermally metamorphosed into hornfels where in contact with Hook Mountain Basalt. Conglomerate and conglomeratic sandstone with subrounded quartzite and quartz clasts in matrix of light-red sand to brownish-red silt (Jtc) interfingers with rocks of the Towaco Formation north and west of New Vernon. Maximum thickness is about 380 m (1,250 ft).
Towaco Formation Conglomerate and Sandstone facies (Lower Jurassic)
Towaco Formation Conglomerate and Sandstone facies - Conglomerate and conglomeratic sandstone with subrounded quartzite and quartz clasts in matrix of light-red sand to brownish-red silt (Jtc) interfingers with rocks of the Towaco Formation north and west of New Vernon.
Wantage Sequence (Middle Ordovician)
Wantage Sequence (Monteverde and Herman, 1989) - Restricted, discontinuous sequence of interbedded limestone, dolomite, conglomerate, siltstone, and shale. Upper part is medium-yellowish-brown- to olive-gray-weathering, medium- to dark-gray, very fine to fine-grained, laminated to massive limestone and dolomite that grade down into underlying clastic rocks of lower part. Upper part locally absent. Lower part ranges from grayish-red, medium-gray, pale-brown, and greenish-gray to pale-green mudstone and siltstone containing disseminated subangular to subrounded chert-gravel, quartz-sand lenses, and chert-pebble conglomerate. Lower contact unconformable. Thickness ranges from 0 to 46 m (0-150 ft).
New Mexico
Abo and Yeso Formations (Phanerozoic | Paleozoic | Permian)
Abo and Yeso Formations, undivided
Abo Formation (Phanerozoic | Paleozoic | Permian)
Abo Formation; red beds, arkosic at base, finer and more mature above; Wolfcampian; may include limestone beds of Pennsylvanian age (Virgilian) in Zuni Mountains. In Robledo Mountains the Abo may be considered a member of the Hueco Formation
Abo Formation, lower part (Phanerozoic | Paleozoic | Permian)
Lower part of Abo Formation; Wolfcampian, and in part Virgilian ?
Bull Canyon Formation of Chinle Group (Phanerozoic | Mesozoic | Triassic)
Bull Canyon Formation; Norian
Bursum Formation (Phanerozoic | Paleozoic | Permian)
Bursum Formation; shale, arkose, and limestone; earliest Permian
Dakota Sandstone and Rio Salado Tongue of the Mancos Shale (Phanerozoic | Mesozoic | Cretaceous)
Dakota Sandstone and Rio Salado Tongue of the Mancos Shale. In northwest Socorro County locally includes overlying Tres Hermanos Formation
Fence Lake Formation (Phanerozoic | Cenozoic | Tertiary)
Fence Lake Formation; conglomerate and conglomeratic sandstone, coarse fluvial volcanoclastic sediments, minor eolian facies, and pedogenic carbonates of the southern Colorado Plateau region; Miocene
Garita Creek Formation of Chinle Group (Phanerozoic | Mesozoic | Triassic)
Garita Creek Formation; Carnian
Gila Group (Phanerozoic | Cenozoic | Tertiary Quaternary)
Gila Group. Includes Mimbres Formation and several informal units in southwestern basins; Middle Pleistocene to uppermost Oligocene
Hueco Formation (Phanerozoic | Paleozoic | Permian)
Hueco Formation; limestone unit restricted to south-central area; Pendejo Tongue divides Abo Formation into upper and lower parts; Wolfcampian
McRae Formation (Phanerozoic | Mesozoic | Cretaceous)
McRae Formation; Engle basin - Cutter sag area; Maastrichtian
Mesaverde Group (Phanerozoic | Mesozoic | Cretaceous)
Mesaverde Group includes the Gallup Sandstone, Crevasse Canyon Formation, Point Lookout Sandstone, Menefee Formation, and Cliff House Sandstone
Moenkopi Formation (Phanerozoic | Mesozoic | Triassic)
Moenkopi Formation; Middle Triassic
Nacimiento Formation (Phanerozoic | Cenozoic | Tertiary)
Nacimiento Formation; Paleocene, San Juan Basin
Ojo Alamo Formation (Phanerozoic | Cenozoic | Tertiary)
Ojo Alamo Formation; Paleocene, San Juan Basin
Poison Canyon and Raton Fromations (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Poison Canyon and Raton Formations; undivided
Raton Formation (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Raton Formation; in Raton Basin; unit contains conformable K/T boundary
Sandia Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian)
Sandia Formation; predominately clastic unit (commonly arkosic) with minor black shales, and limestone in lower part; locally includes Osha Canyon Formation in Nacimiento Mountains
Santa Rosa Formation of Chinle Group (Phanerozoic | Mesozoic | Triassic)
Santa Rosa Formation; Carnian; includes Moenkopi Formation (Middle Triassic) at base in most areas
silicic flows, domes, and associated pyroclastic rocks (Phanerozoic | Cenozoic | Tertiary)
Lower Oligocene silicic (or felsic) flows, domes, and associated pyroclastic rocks and intrusions; includes Mimbres Peak Formation
Nevada
Antler Sequence of Silberling and Roberts (1962) (Pennsylvanian to Late Permian )
ANTLER SEQUENCE OF SILBERLING AND ROBERTS (1962) (Middle Pennsylvanian to Early or Late Permian) (Guadalupian)-Conglomerate, sandy to conglomeratic limestone, limestone, sandstone, and calcareous shale. Thin detrital and carbonate sequence within main part of Antler orogenic belt. Includes units such as Sunflower Formation of Bushnell (1967) in Elko County, Battle Formation, Antler Peak Limestone, and Edna Mountain Formation in Lander and western Eureka Counties, and Wildcat Peak Formation in northern Nye County
Chert, shale, argillite, siltstone, quartzite, and greenstone (Cambrian to Devonian)
CHERT, SHALE, ARGILLITE, SILTSTONE, QUARTZITE, AND GREENSTONE-Undivided siliceous assemblage. Mostly Ordovician
Cherty limestone and sparse dolomite, shale, and sandstone (Permian)
CHERTY LIMESTONE AND SPARSE DOLOMITE, SHALE, AND SANDSTONE (Lower and Upper Permian)-Includes units such as Park City Group and equivalent rocks in northern Nevada and Toroweap Formation and Kaibab Limestone in southern Nevada
Chinle Formation and associated rocks (Late Triassic)
CHINLE FORMATION AND ASSOCIATED ROCKS (Upper Triassic)-Continental deposits of variegated bentonitic claystone, siltstone, and clayey sandstone; ledge-forming sandstone; and red siltstone
Conglomerate, limestone, meta-andesite, phyllite, and shale (Devonian to Mississippian)
CONGLOMERATE, LIMESTONE, META-ANDESITE, PHYLLITE, AND SHALE-Includes Grossman, Banner, Nelson, and Mountain City Formation. Northern Elko County
Conglomerate, sandstone, shale, and dolomite of Diablo Formation below and shale, sandstone, and conglomerate of Candelaria Formation above (Early Permian to Early Triassic)
CONGLOMERATE, SANDSTONE, SHALE, AND DOLOMITE OF DIABLO FORMATION BELOW AND SHALE, SANDSTONE, AND CONGLOMERATE OF CANDELARIA FORMATION ABOVE (Lower or Upper Permian to Lower Triassic)-Mineral, Esmeralda, and northwestern Nye Counties
Continental deposits of siltstone, shale, conglomerate, and limestone (Cretaceous)
CONTINENTAL DEPOSITS OF SILTSTONE, SHALE, CONGLOMERATE, AND LIMESTONE-Includes units such as King Lear Formation in Humboldt County, Newark Canyon Formation in Eureka County, Willow Tank Formation and baseline Sandstone in Clark County
Continental sedimentary rocks (Late Cretaceous to Eocene)
CONTINENTAL SEDIMENTARY ROCKS-Includes units such as Pansy Lee Conglomerate in Humboldt County, part of Cretaceous(?) and Tertiary rocks of Kleinhampl and Ziony (1967) in northern Nye County, and part of "older clastic rocks" of Tschanz and Pampeyan (1970) in Lincoln County
Continental sedimentary rocks (Late Cretaceous to Early Miocene)
CONTINENTAL SEDIMENTARY ROCKS-Clark County
Dolomite, limestone, and minor amounts of sandstone and quartzite (Devonian)
DOLOMITE, LIMESTONE, AND MINOR AMOUNTS OF SANDSTONE AND QUARTZITE-Includes units such as Sevy and Simonson Dolomites, Guilmette and Nevada Formations, and Devils Gate Limestone.
Dunlap Formation (Early Jurassic to Middle Jurassic)
DUNLAP FORMATION (Lower and Middle Jurassic)-Conglomerate, sandstone, greenstone, felsite, and tuff. Locally contemporaneous with folding and thrusting. Mineral County and adjacent parts of Esmeralda and Nye Counties
Gabbroic complex (Early Jurassic to Middle Jurassic)
GABBROIC COMPLEX (Lower and Middle Jurassic)-Includes gabbro, basalt, and synorogenic quartz sandstone (Boyer Ranch Formation). Churchill and Pershing Counties
Harmony Formation (Late Cambrian)
HARMONY FORMATION (Upper Cambrian)-Feldspathic and arkosic sandstone and minor amounts of shale, limestone, and chert.
Havallah sequence of Silberling and Roberts (1962) (Mississippian to Permian)
HAVALLAH SEQUENCE OF SILBERLING AND ROBERTS (1962)-Chert, argillite, shale, greenstone, and minor amounts of siltstone, sandstone, conglomerate, and limestone. Includes Schoonover Formation of Fagan (1962) and Reservation Hill Formation in Elko County, Farrel Canyon Formation in southwestern Humboldt County, Havallah and Pumpernickel Formations in Pershing, Lander, and parts of Humboldt Counties, and rocks originally considered a part of the Pablo and Excelsior Formations in northern Nye, northern Esmeralda, and southern Mineral Counties. Assignment of some rocks to the Havallah sequence in the East Range, Pershing County, is highly uncertain. Includes rocks ranging in age from Late Mississippian to Early Permian
Limestone and dolomite, locally thick sequences of shale and siltstone (Late Cambrian to Middle Cambrian)
LIMESTONE AND DOLOMITE, LOCALLY THICK SEQUENCES OF SHALE AND SILTSTONE-Includes units such as Pioche Shale, Eldorado Dolomite, Geddes Limestone, Secret Canyon Shale, Hamburg Dolomite, Dunderberg Shale, and Windfall Formation of northern Nevada and Carrara, Bonanza King, and Nopah Formations of southern Nevada.
Limestone and sparse dolomite, siltstone, and sandstone (Mississippian to Early Permian)
LIMESTONE AND SPARSE DOLOMITE, SILTSTONE, AND SANDSTONE-Includes units such as undivided Riepe Spring Limestone of Steele (1960) and Ely Limestone or their equivalent in Elko, White Pine, and northern Lincoln Counties and most of the Bird Spring Formation and Callville Limestone in Clark and southern Lincoln Counties. Includes some stratigraphically higher Permian rocks in Leppy Peak, easternmost Elko County.
Limestone, cherty limestone, sandy limestone, and chert-pebble conglomerate (Pennsylvanian)
LIMESTONE, CHERTY LIMESTONE, SANDY LIMESTONE, AND CHERT-PEBBLE CONGLOMERATE (Lower and Middle Pennsylvanian)-Includes units such as Moleen and Tomera Formations of Dott (1955)
Limestone, dolomite, and shale (Mississippian to Permian)
LIMESTONE, DOLOMITE, AND SHALE (Upper Paleozoic)-Includes Van Duzer Limestone of Decker (1962)
Limestone, minor amounts of dolomite, shale, and sandstone; locally thick conglomerate units (Triassic)
LIMESTONE, MINOR AMOUNTS OF DOLOMITE, SHALE, AND SANDSTONE; LOCALLY THICK CONGLOMERATE UNITS (Lower, Middle, and Upper Triassic)-Includes Tobin, Dixie Valley, Favret, Augusta Mountain, and Cane Spring Formations and Star Peak Group in central Nevada and Grantsville and Luning Formations in west-central Nevada
Massive limestone (Mississippian)
MASSIVE LIMESTONE-In the San Antonio Mountains, western Nye County
Moenkopi Formation, Thaynes Formation, and related rocks (Early Triassic to Middle Triassic)
MOENKOPI FORMATION, THAYNES FORMATION, AND RELATED ROCKS (Lower Triassic)-Marine deposits of siltstone, limestone, and sparse conglomerate
Quartzite and minor amounts of conglomerate, phyllitic siltstone, limestone, and dolomite (Late Proterozoic to Early Cambrian)
QUARTZITE AND MINOR AMOUNTS OF CONGLOMERATE, PHYLLITIC SILTSTONE, LIMESTONE, AND DOLOMITE-Includes Prospect Mountain Quartzite, Osgood Mountain Quartzite, and Gold Hill Formation in northern Nevada, and Stirling Quartzite, Wood Canyon Formation, and Zabriskie Quartzite in southern Nevada.
Quartzite, phyllitic siltstone, conglomerate, limestone, and dolomite (Late Proterozoic)
QUARTZITE, PHYLLITIC SILTSTONE, CONGLOMERATE, LIMESTONE, AND DOLOMITE-Includes McCoy Creek Group (excluding Stella Lake Quartzite) in east-central Nevada and Johnnie Formation in southern Nevada.
Sandy and silty limestone, conglomerate, and siltstone (Pennsylvanian to Late Permian)
SANDY AND SILTY LIMESTONE, CONGLOMERATE, AND SILTSTONE (Upper Pennsylvanian to Upper Permian)-Includes units such as Strathearn Formation of Dott (1955) and Buckskin Mountain, Beacon Flat, and Carlin Canyon Formations of Dott (1955)
Sedimentary rocks (Late Cretaceous to Oligocene)
SEDIMENTARY ROCKS-Includes Sheep Pass Formation (Eocene) and related units and unnamed tuffaceous sedimentary rocks
Shale and thin-bedded or laminated limestone; also thinly interbedded limestone and chert (Middle Cambrian to Late Cambrian)
SHALE AND THIN-BEDDED OR LAMINATED LIMESTONE; ALSO THINLY INTERBEDDED LIMESTONE AND CHERT-Includes units such as Preble and Emigrant Formations
Shale, mudstone, siltstone, sandstone, and carbonate rock; sparse volcanic rock (Late Triassic to Early Jurassic)
SHALE, MUDSTONE, SILTSTONE, SANDSTONE, AND CARBONATE ROCK; SPARSE VOLCANIC ROCK (Upper Triassic and Lower Jurassic)-Includes Auld Lang Syne Group, Nightingale sequence of Bonham (1969), and Gabbs and Sunrise Formations
Shale, siltstone, sandstone, chert-pebble conglomerate, and limestone (Devonian to Mississippian)
SHALE, SILTSTONE, SANDSTONE, CHERT-PEBBLE CONGLOMERATE, AND LIMESTONE-Includes units such as Pilot Shale, Joana Limestone, Chainman Shale, and Diamond Peak Formation in northern and eastern Nevada and Narrow Canyon Limestone, Mercury Limestone, and Eleana Formation in southern Nevada
Siliceous and volcanic rocks (Ordovician to Devonian)
SILICEOUS AND VOLCANIC ROCKS-Chert, shale, quartzite, greenstone, and minor amounts of limestone. Includes units such as Valmy Formation of north-central Nevada and some rocks mapped as Palmetto Formation in northern part of Esmeralda County and adjacent parts of Mineral and Nye Counties. Locally includes rocks of Silurian and Devonian age.
Siliceous and volcanic rocks (Mississippian)
SILICEOUS AND VOLCANIC ROCKS-In Humboldt County, consists of altered pillow lavas, coarse volcanic breccias, clastic limestone, and minor amounts of sandstone, shale, siliceous shale, and chert of the Goughs Canyon Formation (Lower and Upper Mississippian). In the East Range, Pershing County, consists of quartzite, conglomerate, slate, limestone, chert, and greenstone of the Inskip Formation (Mississippian?).
Tuffaceous sedimentary rocks (Early Oligocene to Early Miocene)
TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff
Tuffaceous sedimentary rocks (Late Eocene to Late Miocene)
TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff
Volcanic flows and flow breccias, chiefly of andesitic composition, tuffs, sparse sandstone and graywacke (Permian to Jurassic)
VOLCANIC FLOWS AND FLOW BRECCIAS, CHIEFLY OF ANDESITIC COMPOSITION, TUFFS, SPARSE SANDSTONE AND GRAYWACKE-Includes Happy Creek Volcanic Series and related rocks in Humboldt County and similar rocks in Washoe and Pershing Counties; includes andesite breccias and volcanogenic sedimentary rocks in Mineral County
Volcanogenic sedimentary rocks, tuff, andesite and felsitic flows, and carbonate rocks (Permian to Jurassic (?))
VOLCANOGENIC SEDIMENTARY ROCKS, TUFF, ANDESITIC AND FELSITIC FLOWS, AND CARBONATE ROCKS-Age uncertain. Mineral, Esmeralda, and Northwest Nye Counties
New York
Bloomsburg Formation (Upper Silurian)
Bloomsburg Formation - shale, sandstone; Guymard Quartzite; Otisville Shale; Shawangunk Conglomerate-sandstone, conglomerate.
Brunswick Formation (Upper Triassic)
Brunswick Formation - sandstone and conglomerate.
Brunswick Formation, undivided (Upper Triassic)
Brunswick Formation, undivided - includes the units: TRbg: sandstone and conglomerate; TRbs: sandstone, siltstone, mudstone; TRba: mudstone, sandstone, and arkose.
Cheshire Quartzite and Dalton Formation (Cambrian)
Cheshire Quartzite and Dalton Formation
Clinton Group (Silurian)
Clinton Group - Herkimer Sandstone including Joslin Hill and Jordanville Members; Kirkland Hematite; Willowvale Shale; Westmoreland Hematite; Sauquoit Formation-sandstone, shale; Otsquago Sandstone; Oneida Conglomerate.
Clinton Group (Lower Silurian)
Clinton Group - Herkimer Sandstone; Kirkland Hematite; Willowvale Shale; Westmoreland Hematite; Sauquoit Formation-sandstone, shale; Oneida Conglomerate.
Connoquenessing and Sharon Formations (Lower Pennsylvanian)
Connoquenessing and Sharon Formations - sandstone, shale; Sharon Formation-shale, sandstone, conglomerate; Olean Conglomerate 50-100 ft. (15-30 m).
Cuyahoga and Knapp Formations (Lower Mississippian)
Cuyahoga and Knapp Formations - Cuyahoga Formation-shale, sandstone; Corry Sandstone; Knapp Formation-shale, conglomerate 60-100 ft. (20-30 m).
Germantown Formation (Cambrian)
Germantown Formation - south of Troy; shale, conglomerate, limestone.
Germantown Formation (Cambrian)
Germantown Formation - shale, limestone, conglomerate.
Glenerie Formation (Lower Devonian)
Glenerie Formation - limestone, chert.
Hammer Creek Formation (Upper Triassic)
Hammer Creek Formation - conglomerate.
Lower Walton Formation (Upper Devonian)
Lower Walton Formation - shale, sandstone, conglomerate.
Lower Walton Formation (Upper Devonian)
Lower Walton Formation - shale, sandstone, conglomerate.
Medina Group (Lower Silurian)
Medina Group - Grimsby Formation-sandstone, shale.
Mettawee Slate (Cambrian ?)
Mettawee Slate - north of 43 degrees includes Castleton (North Brittain) Conglomerate. Mudd Pond Quartzite, Zion Hill Quartzite, and Bomoseen Graywacke Members.
Mettawee Slate (Cambrian?)
Mettawee Slate (Bull in Vermont) - includes Castleton (North Brittain) Conglomerate. Mudd Pond Quartzite, Zion Hill Quartzite, and Bomoseen Graywacke Members.
Nassau Formation (Cambrian ?)
Nassau Formation - south of 43 degrees; slate, shale, thin quartzite, includes Stuyvesant Conglomerate, Diamond Rock Quartzite, Curtis Mountain Quartzite, and Bomoseen Graywacke Members.
Oneonta Formation (Middle - Upper Devonian)
Oneonta Formation - shale, sandstone, conglomerate.
Oswayo and Venango Formations (Upper Devonian)
Oswayo and Venango Formations - shale, siltstone, sandstone; replaced eastwardly by Cattaraugus Formation-shale, sandstone, conglomerate.
Poughquag Quartzite (Cambrian)
Poughquag Quartzite - (includes local Dalton Formation at base)-locally conglomeratic.
Poultney Formation ("A" Member) (Cambrian)
Poultney Formation ("A" Member) - shale, limestone; Hatch Hill Formation-shale, dolostone; West Castleton Formation-shale, limestone, conglomerate.
Poultney Formation ("A" Member) (Cambrian)
Poultney Formation ("A" Member) - north of Troy: shale, limestone; Hatch Hill Formation-shale, dolostone; West Castleton Formation-shale, limestone, conglomerate.
Quassaic Quartzite (Upper Ordovician)
Quassaic Quartzite - quartzite, sandstone, conglomerate.
Slide Mountain Formation (Upper Devonian)
Slide Mountain Formation - sandstone, shale, conglomerate.
Slide Mountain Formation (Upper Devonian)
Slide Mountain Formation - sandstone, shale, conglomerate.
Slide Mountain Formation (Upper Devonian)
Slide Mountain Formation - sandstone, shale, conglomerate.
Stockton Formation (Upper Triassic)
Stockton Formation - arkose, conglomerate, and mudstone.
Undifferentiated Hamilton Group (Middle Devonian)
Undifferentiated Hamilton Group - shale, siltstone. In eastern Orange County: Skunnemunk Formation-sandstone, conglomerate; Bellvale Formation-shale, sandstone; Cornwall Shale.
Undifferentiated Lower Devonian and Silurian rocks (Lower Devonian - Silurian)
Undifferentiated Lower Devonian and Silurian rocks - in northern Ulster County: Port Ewen thru Manlius Limestones; Rondout Dolostone; Binnewater Sandstone; High Falls Shale. In Orange County: Kanhouse Sandstone; Woodbury Creek Formation-shale, sandstone; Esopus Shale; Connelly Conglomerate; Central Valley Sandstone; New Scotland Limestone thru Rondout Dolostone; Decker Limestone; Poxono Island Formation-shale, dolostone; Longwood Shale; Green Pond Conglomerate.
Undifferentiated Medina Group and Queenston Formation (Upper Ordovician - Lower Silurian)
Undifferentiated Medina Group and Queenston Formation - Grimsby Formation-sandstones, shale; and Queenston Formation-siltstone, shale.
Undifferentiated Medina Group and Queenston Formation (Upper Ordovician - Lower Silurian)
Undifferentiated Medina Group and Queenston Formation - Grimsby Formation-sandstones, shale; and Queenston Formation-shale, siltstone.
Undifferentiated Middle Ordovician thru Lower Cambrian allochthonous rocks (Cambrian - Ordovician)
Undifferentiated Middle Ordovician thru Lower Cambrian allochthonous rocks - principally pelite; lesser quartzite, limestone, conglomerate, graywacke.
Upper Walton Formation (Upper Devonian)
Upper Walton Formation - shale, sandstone, conglomerate.
Upper Walton Formation (Upper Devonian)
Upper Walton Formation - shale, sandstone, conglomerate.
Ohio
Black Hand Sandstone Member of Cuyahoga Formation (Mississippian)
Black Hand Sandstone Member of Cuyahoga Formation - Sandstone and conglomerate; yellow-gray to white, weathers shades yellow, brown, red, and gray; very fine grained to pebbles, mostly medium to coarse grained with lenses and layers of pebbles; massive to crossbedded to laminated; grades laterally into shale and siltstone; quartzose.
Oklahoma
Ada Group or Ada Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late)
ENID- "Ada Group"- Mainly shale with many limestone layers that are thinner and pinch out southward, where fine-grained sandstones are thicker and more numerous. Near Kansas border, group includes (descending): "Auburn shale" (50 feet thick) at top, underlain by "Wakarusa Limestone," IPaw (2 feet thick), unnamed shale (40 feet thick), "Rulo Limestone" (3 feet thick), unnamed shale (18 feet thick), "Happy Hollow Limestone" (2 feet thick), unnamed shale and sandstone (60 feet thick), "Bird Creek Limestone," IPab (2 feet thick; called "Church Limestone" in Kansas), "Severy-Aarde Shale" (70 feet thick), "Turkey Run Limestone," IPat (2 feet thick; called "Coal Creek Limestone" in Kansas), unnamed shale (30 feet thick), "Pearsonia Limestone" (3 feet thick), unnamed shale (15 feet thick), "Little Hominy Limestone" (22 feet thick), "Deer Creek Limestone (15 feet thick), unnamed shale (10 feet thick), "Plummer Limestone" (2 feet thick), unnamed shale (35 feet thick), and "Beil Limestone Member" (10 feet thick) of "Lecompton Limestone" at base. Total thickness, about 400 feet (120 m). OKLAHOMA CITY- "Ada Group"- Mostly orange-brown fine-grained sandstone and red-brown to gray shale; grades southward into chert conglomerates. Includes the following thin limestone beds and shale units north of North Canadian River (descending): "Auburn Shale" (80 feet thick), "Wakarusa Limestone," IPaw (1 to 6 feet thick), unnamed shale (95 feet thick), "Bird Creek Limestone," IPab (1 to 9 feet thick), "Severy-Aarde Shale" (45 feet thick), "Turkey Run Limestone," IPat (1 foot thick), unnamed shale (45 feet thick), and "Lecompton Limestone" (1.5 to 10 feet thick), at base. Total thickness of group ranges from 100 feet in south to 280 feet in north. ARDMORE-SHERMAN- "Ada Formation"- (= Collings Ranch Conglomerate) Shale, red-brown to gray, bituminous sandstone, and limestone conglomerate; thickness, 100 to 1,400 feet (subsurface), decreasing southward.
Antlers Sand or Antlers Sandstone (Phanerozoic | Mesozoic | Cretaceous-Early )
ARDMORE-SHERMAN- "Antlers Sand" Sand, white to yellow, medium-grained, weakly indurated, with varicolored clays. Contains arkosic conglomerates near Arbuckle Mountains and "Baum Limestone" near Mannsville anticline. Thickness, 200 to 700 feet. McALESTER TEXARKANA- "Antlers Sandstone" Sandstone and sand, white to reddish-yellow to orange-brown to gray, fine- to coarse-grained, quartzose, crossbedded, moderately to weakly indurated, interbedded with varicolored clays and conglomerates; contains fossil wood and dinosaurs; rests unconformably upon Ouachita rocks but conformably upon DeQueen Limestone; thickness, 0 to 320 feet, thickening southeastward to 900 feet in subsurface.
Arkansas Novaculite (Phanerozoic | Paleozoic | Silurian Devonian(?) Carboniferous Mississippian-Early )
McALESTER TEXARKANA- Chert, fine- to very fine-grained, gray, green, tan, black, white, and pink, with interbedded black to gray shale in 1-to 18-inch beds; some interbedded conglomerates and in places a basal conglomerate; upper part has been determined to be Mississippian in age and lower part to be Early Silurian, on basis of examination of palynomorphs from Potato Hills; thickness, 600 feet or more. Occurs in the OUACHITA MTNS SOUTH OF TI VALLEY FAULT.
Atoka Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
TULSA- IPat "Atoka Formation," shale, siltstone, sandstone, and thin limestone. FORT SMITH- IPat "Atoka Formation," shale and sandstone. ARDMORE-SHERMAN- Shale, dark-gray, and sandstone, buff to white, fine- to coarse-grained, with some chert conglomerates; thickness, 800 to 3,000 feet. McALESTER TEXARKANA- Shale, gray to tan, illitic, chloritic, with many sandstones, fine- to coarse-grained, quartzose, micaceous, well- to poorly sorted; "Fanshawe" and "Red Oak Sandstones" in middle and "Spiro Sandstone" at base; thickness, 3,000 to 10,000 feet, increasing southeastward in subsurface, south of growth faults.
Carlton Rhyolite Group (Phanerozoic | Paleozoic | Cambrian-Middle)
CLINTON- Rhyolite flows and tuffs; about 4,500 feet thick; one outlier is shown in southern part of mapped area. LAWTON- Rhyolite flows, tuffs, conglomerate beds, and diabase sills; thickness, 4,500 feet (1,370 m).
Chickasha Formation (Phanerozoic | Paleozoic | Permian )
WOODWARD- The "Chickasha Formation" member of Flower Pot Shale (Pc) is a deltaic tongue of red-brown to greenish-gray to orange-brown cross-bedded mudstone conglomerate, siltstone, shale, and fine-grained sandstone, about 30 feet thick, in the middle of the Flowerpot Shale, pinching out northward. CLINTON- "Chickasha Formation," Pc, reddish-brown to maroon mudstone conglomerate with some shale, silstone, and fine- to coarse-grained sandstone; thickness, about 600 feet; gradational northward and westward into the Flowerpot Shale and the Blaine Formation and westward into Dog Creek Shale. OKLAHOMA CITY-Variegated mudstone conglomerate and red-brown to orange- brown silty shale and siltstone, with minor amounts of orange-brown fine-grained sandstone; upper part grades northward into "Dog Creek Shale", "Blaine Formation", "Flowerpot Shale", and upper part of "Cedar Hills Sandstone"; lower part grades into "Duncan Sandstone". Thickness, about 100 feet near Chickasha and 300 feet near Okarche. (El Reno Group) ARDMORE-SHERMAN- Mudstone conglomerate, siltstone, and sandstone, red-brown; thickness, 100 to 200 feet, decreasing southeastward. (El Reno Group)
Coffeyville and Checkerboard Formations or Checkerboard Limestone (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
ENID- "Coffeyville Formation" is mainly shale interbedded with fine-to medium-grained sandstone. Locally formation contains thin coal seams. Thickness ranges from 175 to 470 feet (50 to 140 m). Underlying "Checkerboard Limestone" is crystalline limestone 2 to 15 feet (1 to 5 m) thick. TULSA- "Coffeyville Formation," shale and thin-bedded sandstone. "Checkerboard Formation," limestone and some shale. OKLAHOMA CITY- "Coffeyville Formation," mainly shale interbedded with fine- to medium-grained sandstone locally containing chert and limestone conglomerate and thin coal seams; thickness, 150 to 470 feet. Underlying "Checkerboard Limestone," crystalline limestone 2.5 to 5 feet thick.
Coffeyville or Francis Formation (restricted) (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
ARDMORE-SHERMAN- Shale, dark-blue, 20 to 70 feet thick, with "DeNay Limestone," yellow, massive, 2 to 6 feet thick at base, and 20 feet or more of buff fine- to coarse-grained sandstone and chert conglomerate at top. (Upper Franks Conglomerate)
Cool Creek and McKenzie Hill Formations (Phanerozoic | Paleozoic | Ordovician-Early)
LAWTON- "Cool Creek Formation" and "McKenzie Hill Formation," Ocm, limestone and conglomerate with abundant quartz sand and cherty zones; thickness, approximately 2,000 feet (600 m). (Upper part of Arbuckle Group) ARDMORE-SHERMAN- Limestone, gray to tan, fine-grained, cherty, gradational eastward into dolomites and sandstones; thickness, 1,500 to 2,300 feet, decreasing eastward. (Arbuckle Group) Occurs in the ARBUCKLE MTNS
Crystal Mountain Sandstone (Phanerozoic | Paleozoic | Ordovician-Early)
McALESTER TEXARKANA- Sandstone, pink to light-gray to dark-gray, fine- to coarse-grained, quartzose, with well-rounded, frosted grains, quartzitic, fractured in many places, with many quartz and orthoclase veins; 14-foot chert- and limestone-pebble conglomerate occurs at base; thickness, 500 feet or more, with maximum thickness in Arkansas 850 feet (called Lower Cool Creek in Arbuckle Mountains and Roubidoux Sandstone in Ozarks). Occurs in POTATO HILLS, BROKEN BOW UPLIFT or ADJACENT SMALLER UPLIFTS IN SOUTHEASTERN PART OF OUACHITA MOUNTAINS
Dakota Group (Phanerozoic | Mesozoic | Cretaceous-Early )
CLINTON- Outliers of the "Kiowa Formation," Kk, dark-gray shale with some thin beds of fossiliferous tan limestone, range in thickness from a few feet to about 20 feet. Associated in some places is a 5- to 10-foot, gray to brown, coarse-grained sandstone and conglomerate assigned to the overlying "Dakota Group," Kd, (lower sandstone part).
Deese Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
ARDMORE-SHERMAN- Member of Glenn Fm, mainly massive sandstone, conglomerate and shale. Base of "Confederate Limestone" down to top of "Otterville Limestone;" thickness, 9,700 feet. Occurs in the ARDMORE BASIN
DeQueen Limestone (Phanerozoic | Mesozoic | Cretaceous-Early )
McALESTER TEXARKANA- Limestone and marl, blue- to pinkish- to yellowish-gray, locally siliceous, interbedded with varicolored calcareous shales; basal limestone conglomerate in places where unconformable upon Ouachita rocks but absent where conformable on Holly Creek Formation; contains 80 feet of gypsum and anhydrite in subsurface; thickness, 38 feet, lensing out to 1 foot westward but thickening to 190 feet southeastward in subsurface.
Dockum Group (Phanerozoic | Mesozoic | Triassic-Late )
CIMARRON- Upper shale unit: Varicolored siltstone or claystone, conglomerate, fine-grained sandstone, and limestone. Lower sandstone unit: Varicolored, fine- to coarse-grained sandstone with some clay and interbedded shale.
Dornick Hills Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
ARDMORE-SHERMAN- Series of tan shales with limestones, limestone conglomerate and sandstone. Top of "Otterville Limestone" down to base of "Lake Ardmore Sandstone;" thickness 1,800 feet. Occurs in the ARDMORE BASIN
Duncan Sandstone (Phanerozoic | Paleozoic | Permian )
CLINTON- "Duncan Sandstone," Pd, light-gray and reddish-brown, cross-bedded, fine-grained sandstone and mudstone conglomerate with some interbedded yellowish-gray and reddish-brown shales; thickness, about 200 feet; gradational into the Cedar Hills Sandstone northward and into the Flowerpot Shale northward and westward. OKLAHOMA CITY- Mainly red-brown to orange-brown fine-grained sandstone, with some mudstone conglomerate and shale; grades northward into "Cedar Hills Sandstone" and "Chickasha Formation". Thickness, 450 feet near Chickasha, 300 feet near Oklahoma City, and 100 feet or more near Okarche. (El Reno Group) ARDMORE-SHERMAN- Sandstone, white to buff, fine- to coarse-grained, moderately indurated, with interbedded mudstone conglomerates and siltstones; thickness, 100 to 400 feet, decreasing southeastward. (El Reno Group)
El Reno Group (Phanerozoic | Paleozoic | Permian )
CLINTON- Primarily evaporites and reddish-brown shale, with deltaic clastics to the southeast. Where separate formations have not been distinguished, the "El Reno Group" is mapped as Per; El Reno Group. Includes: "Dog Creek Shale," Pdc, reddish-brown shale with thin beds of siltstone and dolomite; thickness, about 220 feet; gradational eastward into the Chickasha Formation. "Blaine Formation," Pb, 3 to 4 gypsum and dolomite beds, about 100 to 200 feet thick, separated by reddish-brown shale. Gradational southward and eastward into Chickasha Formation. "Flowerpot Shale," Pf, reddish-brown shale containing several salt and gypsum beds in the upper part. Thickness, about 300 to 450 feet; gradational southward and eastward into Chickasha Formation and Duncan Sandstone. "Cedar Hill Sandstone," Pch, greenish-gray sandstone and reddish-brown shales; thickness, about 180 feet; gradational southward into Duncan Sandstone. "Chickasha Formation," Pc, reddish-brown to maroon mudstone conglomerate with some shale, silstone, and fine- to coarse-grained sandstone; thickness, about 600 feet; gradational northward and westward into the Flowerpot Shale and the Blaine Formation and westward into Dog Creek Shale. "Duncan Sandstone," Pd, light-gray and reddish-brown, cross-bedded, fine-grained sandstone and mudstone conglomerate with some interbedded yellowish-gray and reddish-brown shales; thickness, about 200 feet; gradational into the Cedar Hills Sandstone northward and into the Flowerpot Shale northward and westward. LAWTON- Primarily evaporites and reddish-brown shale, with deltaic clastics to the east. In the eastern part of the quadrangle, separate formations have not been distinguished, and the "El Reno Group" is mapped as Per; in the western part of the quadrangle, the group has been mapped as four separate formations. "El Reno Group undifferentiated," Per, in northeastern part of the quadrangle, includes "Chickasha Formation" sandstone, shale, and siltstone, 400 to 580 feet (120 to 180 m) thick-and underlying "Duncan Sandstone" (equivalent to San Angelo Sandstone)-sandstone with some shale, 100 to 250 feet (30 to 76 m) thick.
Flowerpot Shale (Phanerozoic | Paleozoic | Permian )
WOODWARD- Red-brown silty shale with some thin gypsum and dolomite beds in upper 50 feet and fine-grained sandstones in upper part to north. The middle and upper parts contain 50 feet or more of rock salt in the immediate subsurface, giving origin to the Ferguson Salt Plain in Blaine County and the Big and Little Salt Plains in Woods and Harper Counties on the Cimarron River. Thickness ranges from 180 feet in north part to 430 feet in south part. The "Chickasha Formation" (Pc) is a deltaic tongue of red-brown to greenish-gray to orange-brown cross-bedded mudstone conglomerate, siltstone, shale, and fine-grained sandstone, about 30 feet thick, in the middle of the Flowerpot Shale, pinching out northward. CLINTON- "Flowerpot Shale," Pf, reddish-brown shale containing several salt and gypsum beds in the upper part. Thickness, about 300 to 450 feet; gradational southward and eastward into Chickasha Formation and Duncan Sandstone. OKLAHOMA CITY- Mostly red-brown silty clay shale with stringers of gypsum (satin spar and selenite); grades southward into "Chickasha Formation". Thickness, 20 to 40 feet. (El Reno Group) LAWTON- "Flowerpot Shale," Pf, reddish-brown and greenish-gray shale, interbedded with greenish-gray siltstone; thickness, about 175 to 195 feet (53 to 59 m).
Garber Sandstone (Phanerozoic | Paleozoic | Permian )
ENID- Mostly orange-brown, fine- to medium-grained quartzose sandstone and conglomerate, grading northward into shale and calcitic siltstone. Thickness, about 600 feet (180 m). (Sumner Group) OKLAHOMA CITY- Mostly orange-brown to red-brown fine-grained sandstone, irregularly bedded with red-brown shale and some chert and mudstone conglomerate. Thickness ranges from 150 feet in south to 400 feet or more in north. (Sumner Group) LAWTON- "Garber Sandstone," Pg, reddish-brown, fine-grained sandstone and mudstone conglomerate, 160 to 210 feet (49 to 64 m) thick, containing a basal sandstone, the "Asphaltum Sandstone Bed," about 10 to 60 feet (3 to 18 m) thick.(Sumner Group) ARDMORE-SHERMAN- Sandstone, red-brown, fine- to coarse-grained; thickness, about 110 to 150 feet, including Fairmont Shale west of Elmore City, Garvin County
Holdenville Formation or Holdenville Shale (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
OKLAHOMA CITY- "Holdenville Shale"- Mainly clay shale with some interbedded fine-grained calcareous sandstone locally containing beds of crystalline limestone. Thickness ranges from 100 to 280 feet. FORT SMITH- "Holdenville Shale"- Shale, thin sandstone and minor limestones. ARDMORE-SHERMAN- "Holdenville Formation"- Shale, blue-gray, with light-brown sandstones and chert conglomerates and 2 prominent limestones--the upper, or "Sasakwa Limestone," white, fine-grained, 1 to 15 feet thick, 35 feet below the top, and the lower, or "Homer Limestone," dark-brown, sandy, 2 to 10 feet thick, 40 to 70 feet below the Sasakwa. Thickness, 210 to 260 feet. (Upper Franks Conglomerate)
Holly Creek Formation (Phanerozoic | Mesozoic | Cretaceous-Early )
McALESTER TEXARKANA- Gravel, composed mostly of quartz and novaculite, with clay and silt, tan to red-brown; unconformable on Ouachita rocks; thickness, 30 to 100 feet, thickening to 1,070 feet in subsurface of southern McCurtain County
Johns Valley Formation or Johns Valley Shale (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early)
ARDMORE-SHERMAN- "Johns Valley Formation"- Shale, dark-gray, with boulder conglomerate; thickness, 425 to 900 feet. Occurs in the OUACHITA MNTS McALESTER TEXARKANA- "Johns Valley Shale"- Shale, dark-gray, with some stringers of Wapanucka-like limestone in northwestern part of area; contains exotic boulders of southern Arbuckle Mountain facies, ranging from Fort Sill to Goddard and as large as 369 feet in diameter; some Wapanucka nodules are not exotic but were formed in place; thickness, 300 to 1,000 feet. Occurs in the OUACHITA MTNS SOUTH OF TI VALLEY FAULT.
Kiowa Formation (Phanerozoic | Mesozoic | Cretaceous-Early )
WOODWARD- Gray and yellow shale and limestone, with many "Texigryphaea" shells locally. At base is 5 to 10 feet of greenish-gray sandstone in places. Thickness ranges up to 140 feet with top eroded. CLINTON- Outliers of the "Kiowa Formation," Kk, dark-gray shale with some thin beds of fossiliferous tan limestone, range in thickness from a few feet to about 20 feet. Associated in some places is a 5- to 10-foot, gray to brown, coarse-grained sandstone and conglomerate assigned to the overlying "Dakota Group," Kd, (lower sandstone part).
Lower part of Arbuckle Group and Timbered Hills Group (Phanerozoic | Paleozoic | Cambrian-Furongian)
LAWTON- Limestone, dolomite, siltstone, sandstone, conglomerate, and shale, with glauconitic and hematitic zones; thickness, 1,200 to 2,000 feet (370 to 600 m), faulted in isolated areas. Lower part of "Arbuckle Group" includes "Signal Mountain Formation, Royer Dolomite," and "Fort Sill Limestone; Timbered Hills Group" includes "Honey Creek Formation" and "Reagan Sandstone."
Missouri Mountain and Polk Creek Shales (Phanerozoic | Paleozoic | Ordovician-Late Silurian)
McALESTER TEXARKANA- Shale, greenish-gray to maroon to black; grades into phyllite in Broken Bow Uplift; contains some thin sandstones and gray conglomerates; a fossiliferous limestone occurs in Southeast quarter section 29, Township 4 South, Range 23 East; mapped as SmOp in Potato Hills, where it is included with Polk Creek Shale; thickness, 60 to 110 feet or less. Occurs in POTATO HILLS, BROKEN BOW UPLIFT or ADJACENT SMALLER UPLIFTS IN SOUTHEASTERN PART OF OUACHITA MOUNTAINS
Missouri Mountain Shale (Phanerozoic | Paleozoic | Silurian)
McALESTER TEXARKANA- Shale, greenish-gray to maroon to black; grades into phyllite in Broken Bow Uplift; contains some thin sandstones and gray conglomerates; a fossiliferous limestone occurs in Southeast quarter section 29, Township 4 South, Range 23 East; mapped as SmOp in Potato Hills, where it is included with Polk Creek Shale; thickness, 60 to 110 feet or less. Occurs in POTATO HILLS, BROKEN BOW UPLIFT or ADJACENT SMALLER UPLIFTS IN SOUTHEASTERN PART OF OUACHITA MOUNTAINS
Morrison Formation (Phanerozoic | Mesozoic | Jurassic-Late )
CIMARRON- Varicolored fine-grained sandstone, limestone, dolomite, shale, and conglomerate 0 to 470 +/- feet thick.
Nellie Bly Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
TULSA- Shale and thin sandstone. ARDMORE-SHERMAN- Shale, siltstone, fine-grained sandstone, chert conglomerate, limestone, and limestone conglomerate, dark-gray to buff; thickness, 200 to 300 feet.
Pine Top Chert (Phanerozoic | Paleozoic | Devonian-Early)
McALESTER TEXARKANA- Limestone, chert, and cherty limestone, gray to light-gray to tan to white and pink; contains Haragan brachiopods; at top is an 8-foot chert conglomerate; base not exposed; thickness, 60 feet. Occurs in the OUACHITA MTNS NORTH OF TI VALLEY FAULT
Pleistocene and Pliocene deposits, undifferentiated (Phanerozoic | Cenozoic | Tertiary Quaternary | Pliocene Pleistocene)
TEXAS- Interfingering beds, tongues, and lenses of sand, silt, clay, gravel, sandstone, caliche, limestone, conglomerate, and volcanic ash. Includes Ogallala and Laverne Formations of Pliocene age and younger deposits of Pleistocene age. Locally the units are tightly cemented by calcium carbonate; other places, they are very poorly consolidated and nearly free of cementing materials. Thickness ranges from 0 to about 800 feet.
Post Oak Conglomerate (Phanerozoic | Paleozoic | Permian )
LAWTON- "Post Oak Conglomerate," Ppo, limestone conglomerate near limestone outcrops; contains zeolite-opal ("Tepee Creek Formation") locally, near gabbro and anorthosite outcrops; arkosic gravel and cobbles near igneous outcrops. These rock types are interbedded with sand, silt, clay, and shale, as much as 500 feet (150 m) thick at surface but several thousand feet thick in subsurface, extending down section into Pennsylvanian rocks.
Purcell Sandstone (Phanerozoic | Paleozoic | Permian )
OKLAHOMA CITY- Red-brown to maroon fine- to coarse-grained sandstone, mudstone conglomerate, and red- brown shale. Thickness, 150 feet. (Hennessey Group) ARDMORE-SHERMAN- Sandstone, red-brown to maroon and greenish-gray, fine- to coarse-grained, with some shale and mudstone conglomerate; thickness, 90 to 150 feet, decreasing southward. (Hennessey Group).
Purgatoire Formation (Phanerozoic | Mesozoic | Cretaceous-Early )
CIMARRON- Kiowa Shale Member: Gray to black fossiliferous shale with sandstone in the upper part. Thickness ranges from 0 to 50 +/- feet. Cheyenne Sandstone Member: Massive, white to buff, fine- to medium-grained sandstone, containing some conglomerate in the lower part, from 0 to 120 +/- feet thick.
San Angelo Sandstone (Phanerozoic | Paleozoic | Permian )
LAWTON- "San Angelo Sandstone," Psa, interstratified sandstone, mudstone conglomerate, and shale, as much as 80 feet (24 m) thick.
Seminole Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
TULSA- Shale, sandstone, and thin coal beds. OKLAHOMA CITY- Chert conglomerate, shale, and fine-grained sandstone containing coal seams in upper part locally. Thickness ranges from 100 to 375 feet. FORT SMITH- Sandy shale, sandstone, and thin coal seams. ARDMORE-SHERMAN- Shale, gray-green, with buff fine-grained sandstones, chert conglomerates, and limy sandstones; thickness, about 120 feet. (Upper Franks Conglomerate)
Thurman Sandstone (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
OKLAHOMA CITY- Mainly medium-grained, silty sandstone with cherty conglomerate at base. Only a few feet exposed in quadrangle. FORT SMITH- Sandstone and shale. ARDMORE-SHERMAN- Sandstone, brown, fine- to coarse-grained, with some gray shale and basal 50-foot chert conglomerate; thickness, 80 to 250 feet, decreasing southwestward. McALESTER TEXARKANA- Sandstone, brown, fine- to coarse-grained, with some gray shale and a basal 50-foot chert conglomerate; grades northward into Boggy Formation; top eroded at many places; thickness, 200 feet.
Vamoosa Group or Vamoosa Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late)
ENID- "Vamoosa Group"- Alternating layers of shale and fine- to coarse-grained sandstone, with some thin limestones. Sandstone layers are thicker, coarser grained, and more numerous southward. Group near Kansas border includes (descending): unnamed shale and sandstone (160 feet thick) at top, "Plattsmouth Limestone, "IPvap (14 to 23 feet thick), unnamed shale and sandstone (15 to 90 feet thick), "Leavenworth Limestone," IPvale (4 feet thick), unnamed shale and sandstone (170 feet thick) "Labadie Limestone," IPval (6 to 23 feet thick; may also be called "Haskell Limestone"), unnamed shale and sandstone (60 to 100 feet thick), "Bowring Limestone," IPvab (2 feet thick; may also be called "Westphalia Limestone"), unnamed shale (5 to 10 feet thick), and basal "Cheshewalla Sandstone (7 to 20 feet thick; also called "Tonganoxie Sandstone"). Total thickness about 630 feet (190 m) OKLAHOMA CITY- "Vamoosa Formation"- Alternating thin to massive layers of fine- to coarse-grained sandstone and sandy, silty shale containing some chert conglomerate in middle and lower parts of formation. Thickness ranges about 200 to about 690 feet. ARDMORE-SHERMAN- "Vamoosa Formation"- Shale, sandstone, and chert conglomerate; red-brown to buff fine- to coarse-grained sandstone. Subdivided into 12 members, each with coarse clastics at base overlain by shale. Thickness, about 125 to 260 feet (to 1,000 feet in subsurface), decreasing southward.
Vanoss Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late)
ENID- Alternating layers of limestone and shale to north, grading southward into limestone, shale, and fine-grained arkosic sandstone. Locally group contains thin coal seams. Near Kansas border, group includes (descending): "Salem Point Shale" (12 feet thick) at top, underlain by "Burr Limestone" (8 feet thick), "Legion Shale" (4 feet thick), "Sallyards Limestone" (3 feet thick), "Roca Shale" (15 feet thick), "Red Eagle Limestone," IPvre (20 feet thick), "Johnson Shale" (35 feet thick), "Long Creek Limestone," IPvlc (10 feet thick), unnamed shale (3 feet thick), "Hughes Creek Limestone (15 feet thick), unnamed shale (12 feet thick), "Americus Limestone, "IPvam, (12 feet thick), "Oaks Shale" (3 feet thick), "Houchen Creek Limestone (8 feet thick), "Stine Shale" (20 feet thick), "Five Point Limestone" (3 feet thick), unnamed shale (12 feet thick), "Brownville Limestone, IPvb (8 feet thick), "Pony Creek Shale" (40 feet thick), "Grayhorse Limestone," IPvg (5 feet thick), unnamed shale (12 feet thick), "Nebraska City Limestone" (5 feet thick), "French Creek Shale" (12 feet thick), "Jim Creek Limestone" (3 feet thick), "Friedrich Shale" (30 feet thick), "Grandhaven Limestone" (2 feet thick), "Dry Shale" (25 feet thick), "Dover Limestone" (30 feet thick), "Willard-Langdon Shale" (110 feet thick), "Elmont Limestone," IPve (10 feet thick), "Stonebreaker Shale" (20 feet thick), and "Reading Limestone" (20 feet thick) at base. Total thickness, about 500 feet (150 m). OKLAHOMA CITY- Red-brown to gray shale and orange-brown fine-grained, crossbedded sandstone; grades southward into arkosic sandstoneand conglomerate. Includes many thin limestone beds and shale units north of North Canadian River (descending): "Roca Shale"(75 feet thick), "Red Eagle Limestone," IPvre (3 to 8 feetthick), "Johnson Shale" (60 feet thick), "Long Creek Limestone," IPvlc (9 to 12 feet thick), "Hughes Creek Shale" (52 feet thick), "Americus Limestone," IPva (1.0 to 2.5 feetthick), "Admire Shale" (70 feet thick), "BrownvilleLimestone," IPvb (1 to 3 feet thick), "Pony Creek Shale" (75 feet thick), "Grayhorse Limestone," IPvg (1 foot thick), unnamed shale (70 feet thick), "Elmont Limestone," IPve (1.2to 7.8 feet thick), "Stonebreaker Shale" (60 feet thick), and"Reading Limestone" (1.5 feet thick), at base. Totalthickness of group ranges from 250 feet in south to 490 feet in north. ARDMORE-SHERMAN- Shale, maroon, arkose, and limestone conglomerate; thickness, 250 to 900 feet (subsurface), decreasing southward. (Pontotoc Group)
Wellington Formation (Phanerozoic | Paleozoic | Permian )
ENID- Mostly red-brown shale to north, grading into fine-grained sandstone and mudstone conglomerate southward into Logan County. Thickness, about 850 feet (260 m). (Sumner Group) OKLAHOMA CITY- Red-brown shale and orange-brown fine-grained sandstone, containing much maroon mudstone conglomerate and chert conglomerate to south. Thickness ranges from about 150 feet in south to 500 feet in north. (Sumner Group) LAWTON- Maroon shale, about 130 feet (40 m) thick, with greenish-gray and black sandstone of the "Ryan Sandstone Bed" at base. (Sumner Group) ARDMORE-SHERMAN- Shale, red-brown, with several 20- to 30-foot bituminous sandstones at base ("Ryan"); thickness, about 100 to 200 feet, decreasing southeastward.
West Spring Creek and Kindblade Formations (Phanerozoic | Paleozoic | Ordovician-Early)
LAWTON- "West Spring Creek Formation" and "Kindblade Formation," Owk, dolomite, dolomitic sandstone, conglomerate, and limestone; thickness, approximately 2,000 feet (600 m). (Upper part of Arbuckle Group). ARDMORE-SHERMAN- Limestone, gray to tan, fine-grained, gradational eastward into tan fine- to coarse-grained dolomite; some tan to gray sandstone and shale; thickness, 1,875 to 3,000 feet, decreasing eastward. (Arbuckle Group) Individual Fm description not found. Occurs in the ARBUCKLE MTNS
Wewoka Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle)
OKLAHOMA CITY- Interbedded fine- to medium-grained sandstone and calcareous shale. Thickness ranges from 400 to 750 feet. FORT SMITH- Shale, sandstone, and minor limestones ARDMORE-SHERMAN- Shale, blue-gray, sandstone, chert conglomerate, and limestone conglomerate; thickness, 400 feet.
Oregon
Clastic sedimentary rocks (Upper and Lower Cretaceous) (Early to Late Cretaceous)
Locally fossiliferous sandstone and conglomerate; marine fossils indicate Early Cretaceous (Albian) age (Jones, 1960). Includes the Hornbrook Formation of Peck and others (1956), the Grove Creek strata of Jones (1960) and Page and others (1977), Hunters Cove Formation, Cape Sebastian Sandstone, Humbug Mountain Conglomerate, and Rocky Point Formation (Dott, 1971; Blake and others, 1985) and clastic sedimentary rocks on the West Fork of the Illinois River near Waldo (Imlay and others, 1959), about 12 km south of Cave Junction
Continental sedimentary rocks (upper and middle Miocene) (Middle Miocene to Late Miocene)
Poorly sorted and poorly bedded, fine- to coarse-grained tuffaceous siltstone, sandstone, pebble conglomerate, agglomerate, volcanic cobble conglomerate, air-fall tuff, and rare basaltic andesite flows equivalent to those in unit Tba. Included in the Miocene Sardine Formation by Peck and others (1964)
Lacustrine and fluvial deposits (Miocene) (Miocene)
Poorly to moderately consolidated, bedded silicic ash and pumicite, diatomite, tuffaceous sedimentary rocks, minor mudflow deposits, and some coarse epiclastic deposits. Vitroclastic material in some beds diagenetically altered to zeolites, secondary silica minerals, and clay minerals. In eastern Blue Mountains province vertebrate fossils indicate unit is mostly of late Miocene (Clarendonian) age, but may also include some rocks of middle Miocene (Barstovian) age. In High Lava Plains and northern Owyhee Upland provinces, vertebrate fossils indicate unit is partly late Miocene (Clarendonian), but probably is mostly middle Miocene (Barstovian) in age. Interfingers and grades laterally into unit Tmb. Includes lake and stream sediments and tuffaceous lake and stream deposits of Prostka (1962, 1967), Deer Butte Formation of Corcoran and others (1962) and Kittleman and others (1967), Juntura Formation of Shotwell and others (1963), some rocks originally assigned to the lower part of the (now obsolete) Danforth Formation of Piper and others (1939), and interbeds in upper part of Columbia River Basalt Group in northern Wallowa County
Marine facies (Middle Eocene to Late Eocene)
Basaltic clastic rocks and pillow lavas, locally mapped separately by Wells and others (1983). Foraminiferal assemblages are assigned to the lower part of the Narizian Stage of Mallory (1959); see Wells and others (1983) for summary
Marine facies (Middle Eocene to Late Eocene)
Basaltic clastic rocks and pillow lavas, locally mapped separately by Wells and others (1983). Foraminiferal assemblages are assigned to the lower part of the Narizian Stage of Mallory (1959); see Wells and others (1983) for summary
Marine sandstone, siltstone, and mudstone (lower Eocene and Paleocene?) (Paleocene to Early Eocene)
Rhythmically interbedded sandstone, siltstone, and mudstone with minor conglomerate; deposited in deep-sea fan depositional setting on submarine basalts of the Siletz River Volcanics. Contains foraminiferal faunas referred to the Penutian Stage of early Eocene age and locally contains assemblages of probable Paleocene age (McKeel and Lipps, 1975; P.D. Snavely, Jr. and David Bukry, written communication, 1980). Included by Diller (1898) in the Umpqua Formation; Baldwin (1974) and Ryberg (1984) mostly mapped unit as sedimentary rocks of the Roseburg Formation of the Umpqua Group; according to Heller and Ryberg (1983) and Molenaar (1985), may be partly correlative with the Lookingglass Formation of Baldwin (1974). Includes lower Eocene-Paleocene turbidite sedimentary rocks exposed at Five Mile Point, about 11 km north of Bandon, that are considered by Snavely and others (1980) to represent allochtonous terrane
Marine sedimentary and tuffaceous rocks (middle Miocene to upper Eocene) (Late Eocene to Middle Miocene)
Tuffaceous and arkosic sandstone, locally fossiliferous, tuffaceous siltstone, tuff, glauconitic sandstone, minor conglomerate layers and lenses, and a few thin coal beds. Includes Scappoose Formation (Trimble, 1963; Wells and others, 1983), mudstone of Oswald West (Niem and Van Atta, 1973; Wells and others, 1983), Pittsburg Bluff Formation (see Wells and others, 1983), and Smuggler Cove and Northrup Creek formations (informal names) of Niem and Niem (1985)
Marine sedimentary rocks (lower Miocene and Oligocene) (Oligocene to Early Miocene)
Fossiliferous marine tuffaceous arkosic sandstone, and lesser conglomerate, sandstone, claystone, nonmarine volcanic sedimentary rocks, and minor coal. Molluscan and vertebrate (Cetacea) fossils indicate late Oligocene and Miocene age (Orr and Miller, 1983; Miller and Orr, 1984b). Includes Butte Creek beds of Harper (1946), and several Miocene and late Oligocene units of Miller and Orr (1984a, b)
Marine sedimentary rocks (lower Pliocene? and upper Miocene) (Late Miocene to Early Pliocene)
Massive, thick-bedded sandstone with minor interbeds of siltstone; local fossiliferous conglomerate lenses. Includes principally the Empire Formation of Baldwin (in Beaulieu and Hughes, 1975), originally considered of Pliocene age, but, on the basis of contained molluscan assemblage, now restricted to a late Miocene age (Addicott, 1983)
Marine siltstone, sandstone, and conglomerate (lower Eocene) (Early Eocene)
Cobble and pebble conglomerate, pebbly sandstone, lithic sandstone, siltstone, and mudstone; massive to thin bedded; shelf and slope depositional setting. Contains foraminiferal faunas referred to the Penutian Stage of early Eocene age. Included by Diller (1898) in the Umpqua Formation; Baldwin (1974) and Ryberg (1984) included it in the Lookingglass Formation of the Umpqua Group of Baldwin; may be partly a shelf and slope facies of the sedimentary rocks of the Roseburg Formation of Baldwin (1974) according to Molenaar (1985) and Heller and Ryberg (1983)
Melange (Jurassic) (Jurassic)
Structurally complex mixture of basaltic rocks, serpentinite, chert, argillite, conglomerate, silty sandstone, and lenses of marble composing the melange of the Takilma area of Smith and others (1982)
Myrtle Group (Lower Cretaceous and Upper Jurassic) (Late Jurassic to Early Cretaceous)
Conglomerate, sandstone, siltstone, and limestone. Locally fossiliferous. As shown, includes Riddle and Days Creek Formations (Imlay and others, 1959; Jones, 1969)
Nonmarine sedimentary rocks (Eocene) (Eocene)
Continentally derived conglomerate, pebble conglomerate, sandstone, siltstone, and mudstone containing abundant biotite and muscovite. Dominantly nonvolcanic; clastic material derived from underlying older rocks
Otter Point Formation of Dott (1971) and related rocks (Upper Jurassic) (Late Jurassic)
Highly sheared graywacke, mudstone, siltstone, and shale with lenses and pods of sheared greenstone, limestone, chert, blueschist, and serpentine. Identified as melange by some investigators
Sedimentary and volcanic rocks (Jurassic and Upper Triassic?) (Late Triassic? to Jurassic)
Olive-drab, pale-brown, dark-gray, and black volcanic graywacke and siltstone; lesser conglomerate and slate, and minor limestone and chert. Includes more extensive outcrops of Triassic or Jurassic limestone at north base of Juniper Mountain in northern Malheur County and near Huntington in southeastern Baker County. Interlayers of silicic and intermediate volcanic rocks are rare. Locally metamorphosed to prehnite-pumpellyite and zeolite facies and in places to greenschist facies. Folded, sheared, and locally foliated. Includes the Weatherby Formation of Brooks (1979). Age is Late Triassic(?) and Early and Middle Jurassic (Sinemurian-Callovian)
Sedimentary rocks (Cretaceous) (Cretaceous)
Marine graywacke, subgraywacke, conglomerate, and shale. Pebbles and cobbles in conglomerate are well rounded volcanic and metavolcanic rocks, low-grade metasedimentary rocks, quartzite, chert, and minor silicic and intermediate plutonic rocks. Shales are gray to black and are fissile to blocky. Sandstones commonly display graded bedding; conglomerate beds are commonly thick and poorly bedded. Shales, near Mitchell, have yielded latest (Early Cretaceous (Albian) fossils; some earliest Late Cretaceous (Cenomanian) fossils occur in beds southeast of Mitchell (D.L. Jones, oral Commun., 1972). Includes Hudspeth and Gable Creek Formations (OR049), Bernard Formation (OR028), and Cretaceous sedimentary rocks (OR008)
Sedimentary rocks of Dothan Formation and related rocks (Lower Cretaceous and Upper Jurassic) (Late Jurassic to Early Cretaceous)
Sandstone, conglomerate, graywacke, rhythmically banded chert lenses. Includes western Dothan and Otter Point Formations of M.C. Blake, Jr. and AS. Jayko (unpublished data, 1985) in Curry and southern Coos Counties
Sedimentary rocks of Dothan Formation and related rocks (Lower Cretaceous and Upper Jurassic) (Late Jurassic to Late Cretaceous)
Sandstone, conglomerate, graywacke, rhythmically banded chert lenses. Includes western Dothan and Otter Point Formations of M.C. Blake, Jr. and AS. Jayko (unpublished data, 1985) in Curry and southern Coos Counties
Sedimentary rocks (Oligocene and upper Eocene) (Late Eocene to Oligocene)
Marine shale siltstone, sandstone, and conglomerate, in places partly composed of tuffaceous and basaltic debris; interbeds of arkosic, glauconitic, and quartzose sandstone. Foraminifers are referable to the Refugian and Zemorrian Stages (see marine sedimentary rocks-units Toes and Toem-of Wells and others, 1983). Includes Bastendorff Formation of Baldwin (1974)
Sedimentary rocks, partly metamorphosed (Triassic and Paleozoic) (Paleozoic to Jurassic(?))
Poorly bedded argillite, chert, phyllite, phyllitic quartzite, calc-phyllite, impure limestone, and marble. In places rocks are strongly foliated. In Klamath Mountains of southwest Oregon, includes shale, mudstone, volcaniclastic sandstone, graywacke, conglomerate, tuff, and minor radiolarian chert and marble of the Applegate Group
Sedimentary rocks (Pleistocene and Pliocene) (Pliocene to Pleistocene)
Semiconsolidated lacustrine and fluvial ashy and palagonitic sedimentary rocks, mostly tuffaceous sandstone and siltstone; locally contains abundant palagonitized basaltic debris and some pebble conglomerate. Includes alluvial gravel and mudflow deposits of Walters Hill and Springwater Formations (Trimble, 1963). In places, grades laterally through palagonite tuff and breccia into basalt flows
Shale, mudstone, and sandstone (Jurassic) (Late Jurassic)
Black to gray shale, mudstone, and sandstone with local lenses of pebble conglomerate. Overlies Josephine ophiolite of Harper (1980) (unit Ju)
Siletz River Volcanics and related rocks (middle and lower Eocene and Paleocene) (Paleocene to Middle Eocene)
Aphanitic to porphyritic, vesicular pillow flows, tuff-breccias, massive lava flows and sills of tholeiitic and alkalic basalt. Upper part of sequence contains numerous interbeds of basaltic siltstone and sandstone, basaltic tuff, and locally derived basalt conglomerate. Rocks of unit pervasively zeolitized and veined with calcite. Most of these rocks are of marine origin and have been interpreted as oceanic crust and seamounts (Snavely and others, 1968). Foraminiferal assemblages referred to the Ulatisian and Penutian Stages (Snavely and others, 1969); K-Ar ages range from 50.7 +/- 3.1 to 58.1 +/- 1.5 Ma (Duncan, 1982); includes the lower part of the Roseburg Formation of Baldwin (1974), which has yielded K-Ar ages as old as 62 Ma
Tillamook Volcanics (upper and middle Eocene) (Middle Eocene to Late Eocene)
Subaerial basaltic flows and breccia and submarine basaltic breccia, pillow lavas, lapilli and augite-rich tuff with interbeds of basaltic sandstone, siltstone, and conglomerate. Includes some basaltic andesite and, near the top of the sequence, some dacite. Potassium-argon ages on middle and lower parts of sequence range from about 43 to 46 Ma (Magill and others, 1981): one potassium-argon age from dacite near top of sequence is about 40 Ma (see Wells and others, 1983)
Tuffaceous sedimentary rocks and tuff (Pliocene and Miocene) (Miocene to Pliocene)
Semiconsolidated to well-consolidated mostly lacustrine tuffaceous sandstone, siltstone, mudstone, concretionary claystone, conglomerate, pumicite, diatomite, air-fall and water-deposited vitric ash, palagonitic tuff and tuff breccia, and fluvial sandstone and conglomerate. Palagonitic tuff and breccia grade laterally into altered and unaltered basalt flows of unit Tob. In places includes layers of fluvial conglomerate and, in parts of the Deschutes-Umatilla Plateau, extensive deposits of fanglomerate composed mostly of Miocene basalt debris and silt. Also includes thin, welded and nonwelded ash-flow tuffs. Vertebrate and plant fossils indicate rocks of unit are mostly of Clarendonian and Hemphillian (late Miocene and Pliocene) age. Potassium-argon ages on interbedded basalt flows and ash-flow tuffs range from about 4 to 10 Ma. Includes the Drewsey Formation of Shotwell and others (1963); sedimentary parts of the Rattlesnake Formation of Brown and Thayer (1966); an interstratified ash-flow tuff has been radiometrically dated by potassium-argon methods at about 6.6 Ma (see Fiebelkorn and others, 1983); Bully Creek Formation of Kittleman and others (1967); Dalles Formation of Newcomb (1966, 1969); Shutler Formation of Hodge (1932), McKay beds of Hogenson (1964) and Newcomb (1966) (see also Shotwell, 1956); Kern Basin Formation of Corcoran and others (1962); Rome beds of Baldwin (1976); parts of the (now obsolete) Danforth Formation of Piper and others (1939), Idaho Group of Malde and Powers (1962), Thousand Creek Beds of Merriam (1910); the Madras (or Deschutes) Formation, the "Simtustus formation" of Smith (1984), and the Yonna Formation (Newcomb, 1958). In areas west of Cascade crest, includes the Sandy River Mudstone and the Troutdale Formation of Trimble (1963) and the lower Pliocene Helvetia Formation of Schlicker and Deacon (1967)
Yaquina Formation (lower Miocene and upper Oligocene) (Late Oligocene to Early Miocene)
Thick- to thin-bedded sandstone, conglomerate, and tuffaceous siltstone of deltaic origin; locally contains thin coal and ash beds. Conglomerate contains abundant clasts of pumice and dacitic volcanic rocks. In places includes thick lenses of marine tuffaceous siltstone and fine-grained sandstone. Foraminifers in formation assigned to the Zemorrian and lower part of the Saucesian Stages of Kleinpell (1938) and molluscan fauna to the lower Blakeley Stage of Weaver and others (1944)
Pennsylvania
Allegheny and Pottsville Formations, undivided (Pennsylvanian)
Allegheny and Pottsville Formations, undivided - Sandstone, shale, and some coal; includes lower Pottsville conglomerate and overlying strata equivalent to Allegheny Formation in north-central outliers; formational boundary not determined due to lack of correlation with Brookville-Clarion coal.
Bald Eagle Formation (Ordovician)
Bald Eagle Formation - Gray to olive-gray and grayish-red, fine- to coarse-grained, crossbedded sandstone, siltstone, and shale; some conglomerate (Lost Run Member); not present east of Susquehanna River, except at Spitzenberg Hill area (Berks County).
Beekmantown Group (Ordovician)
Beekmantown Group - Includes, in descending order, the Ontelaunee (Oo), Epler (Oe), Rickenbach (Ori), and Stonehenge (Os) Formations.
Berea Sandstone through Venango Formation, undivided (Devonian)
Berea Sandstone through Venango Formation, undivided - Greenish-yellow and gray sandstone, siltstone, and shale succession, becoming more shaly and more gray downward; bottom of interval is bottom of Panama Conglomerate; Venango not mapped separately because upper key bed (Woodcock Sandstone) is missing. Includes, in descending order: Berea Sandstone, Bedford Shale, Cussewago Sandstone, Riceville Shale, and Venango Formation equivalent; contains marine fossils.
Burgoon Sandstone (Mississippian)
Burgoon Sandstone - Buff, medium-grained, crossbedded sandstone; includes shale and coal; in places, contains conglomerate at base; contains plant fossils; equivalent to Pocono Formation of Ridge and Valley province.
Burgoon Sandstone through Cuyahoga Group, undifferentiated (Mississippian)
Burgoon Sandstone through Cuyahoga Group, undifferentiated - Informal unit including elements of Burgoon Sandstone and Shenango Formation plus Cuyahoga Group; correlation uncertain; contains sedimentary structures and trace fossils characteristic of tidal flats; called "Pocono" by earlier workers.
Catskill Formation (Devonian)
Catskill Formation - Grayish-red sandstone, siltstone, shale, and mudstone; locally conglomeratic; contains gray sandstone in upper part; lithologies arranged in fining-upward cycles; equivalent to the Hampshire Formation south of Pennsylvania.
Catskill Formation (Devonian)
Catskill Formation - Succession of grayish-red sandstone, siltstone, shale, and mudstone, generally in fining-upward cycles; some gray sandstone and conglomerate.
Chickies Formation (Cambrian)
Chickies Formation - Light-gray, hard, massive, Scolithus-bearing quartzite and quartz schist; thin, interbedded dark slate at top; conglomerate (Hellam Member) at base.
Clarks Ferry Member of Catskill Formation (Devonian)
Clarks Ferry Member of Catskill Formation - Gray to yellowish-gray sandstone, siltstone, and conglomerate.
Clarks Ferry Member of Catskill Formation (Devonian)
Clarks Ferry Member of Catskill Formation - Gray to yellowish-gray sandstone and conglomerate.
Conestoga Formation (Ordovician and Cambrian)
Conestoga Formation - Light-gray, thin-bedded, impure, contorted limestone having shale partings; conglomeratic at base; in Chester Valley, includes micaceous limestone in upper part, phyllite in middle, and alternating dolomite and limestone in lower part.
Decker Formation through Poxono Island Formation, undivided (Silurian)
Decker Formation through Poxono Island Formation, undivided -In descending order: Decker Formation--gray calcareous sandstone having lenses of calcareous conglomerate, siltstone, and shale, and lenses of limestone and dolomite (in Stroudsburg area, includes calcareous shale, limestone, and dolomite of Rondout Formation at top); Bossardville Limestone--gray argillaceous limestone and dolomitic limestone; Poxono Island Formation--thin-bedded dolomite, limestone, and shale; red shale in lower part. This undivided succession is equivalent to Keyser, Tonoloway, and Wills Creek (part) Formations of central Pennsylvania.
Duncannon Member of Catskill Formation (Devonian)
Duncannon Member of Catskill Formation - Grayish-red sandstone, siltstone, and mudstone in fining-upward cycles; conglomerate occurs at base of some cycles.
Duncannon Member of Catskill Formation (Devonian)
Duncannon Member of Catskill Formation - Grayish-red sandstone, siltstone, and mudstone in fining-upward cycles; conglomerate occurs at base of some cycles.
Epler Formation (Ordovician)
Epler Formation - Thick-bedded, medium- to medium-dark-gray, finely crystalline limestone, weathering light gray; yellow dolomitic laminae; interbedded medium-dark-gray, finely crystalline dolomite, weathering yellowish gray; edgewise conglomerate; fossil-fragment and oolitic lenses.
Foreknobs Formation (Devonian)
Foreknobs Formation - Interbedded sandstone, siltstone, and shale; gray to olive gray, red near top; substantial brownish-gray sandstone; some marine fossils; a few conglomerate beds at base and top.
Gettysburg conglomerate (Triassic)
Gettysburg conglomerate - Gray quartz conglomerate, sandstone, and red siltstone and mudstone.
Hamburg sequence rocks (Ordovician)
Hamburg sequence rocks - Predominantly greenish gray, gray, purple, and maroon shale, siltstone, and graywacke; includes some wildflysch having Martinsburg matrix.
Hammer Creek conglomerate (Triassic)
Hammer Creek conglomerate - Cobble and pebble quartz conglomerate interbedded with red sandstone.
Hardyston Formation (Cambrian)
Hardyston Formation - Typically light-gray, fine- to medium-grained quartzite, and feldspathic sandstone; color ranges from nearly white to dark gray; massive bedded; Scolithus present in upper part; quartz-pebble conglomerate occurs at base.
Heidlersburg Member of Gettysburg Formation (Triassic)
Heidlersburg Member of Gettysburg Formation - Red, green, and gray shale and argillite, and minor thin beds of gray arkosic sandstone; some quartz conglomerate and limestone conglomerate.
Irish Valley Member of Catskill Formation (Devonian)
Irish Valley Member of Catskill Formation - Nonmarine, grayish-red siltstone and mudstone, and gray and grayish-red sandstone interbedded with minor, thin, light-olive-gray marine siltstone; arranged in fining-upward cycles. Lower part of member has conglomeratic sandstones.
Juniata and Bald Eagle Formations, undivided (Ordovician)
Juniata and Bald Eagle Formations, undivided - Includes, in descending order, the Juniata (Oj) and Bald Eagle (Obe) Formations.
Limestone fanglomerate (Triassic)
Limestone fanglomerate - Yellowish-gray to medium-gray, angular limestone and dolomite pebbles, cobbles, and fragments set in a red, very fine grained quartz matrix; a few shale-clast interbeds.
Llewellyn Formation (Pennsylvanian)
Llewellyn Formation - Gray, fine- to coarse-grained sandstone, siltstone, shale, conglomerate, and numerous anthracite coals in repetitive sequences.
Lock Haven Formation (Devonian)
Lock Haven Formation - Interbedded olive-gray mudstone, siltstone, sandstone, and thin conglomerate; marine fossils throughout; "Chemung" of earlier workers. Laterally equivalent to Scherr and Foreknobs Formations.
Marburg Schist (Probably lower Paleozoic)
Marburg Schist - Gray-green phyllite, mica-chlorite schist, and conglomerate.
Mauch Chunk Formation (Mississippian)
Mauch Chunk Formation - Grayish-red shale, siltstone, sandstone, and some conglomerate; some local nonred zones. Includes Loyalhanna Member (crossbedded, sandy limestone) at base in south-central and southwestern Pennsylvania; also includes Greenbrier Limestone Member, and Wymps Gap and Deer Valley Limestones, which are tongues of the Greenbrier. Along Allegheny Front from Blair County to Sullivan County, Loyalhanna Member is greenish-gray, calcareous, crossbedded sandstone.
New Oxford conglomerate (Triassic)
New Oxford conglomerate - Quartz or quartzite pebbles, cobbles, and rare boulders set in a red, sandy, ferruginous matrix; some silica cement; some feldspar clasts.
Nittany and Stonehenge/Larke Formations, undivided (Ordovician)
Nittany and Stonehenge/Larke Formations, undivided - Includes, in descending order, the Nittany (On) and Stonehenge/Larke (Osl) Formations.
Packerton Member of Catskill Formation (Devonian)
Packerton Member of Catskill Formation - Greenish-gray to gray sandstone and some siltstone; some laterally persistent conglomerate beds in lower part.
Peach Bottom Slate and Cardiff Conglomerate, undivided (Probably lower Paleozoic)
Peach Bottom Slate and Cardiff Conglomerate, undivided - Bluish-black slate (Peach Bottom); quartz conglomerate having a matrix of sericite and chlorite (Cardiff).
Pocono and Rockwell Formations, undivided (Mississippian and Devonian)
Pocono and Rockwell Formations, undivided: Buff, medium-grained, crossbedded sandstone and some conglomerate (Pocono), overlying buff to olive-gray, fine- to medium-grained, crossbedded sandstone containing a few beds of shale and conglomerate (Rockwell); shown in southwestern Bedford County only.
Pocono Formation (Mississippian)
Pocono Formation - Light-gray to buff or light-olive-gray, medium-grained, crossbedded sandstone and minor siltstone; commonly conglomeratic at base and in middle; medial conglomerate, where present, is used to divide into Mount Carbon and Beckville Members; equivalent to Burgoon Sandstone of Allegheny Plateau.
Poplar Gap and Packerton Members of Catskill Formation, undivided (Devonian)
Poplar Gap and Packerton Members of Catskill Formation, undivided - Includes, in descending order, the Poplar Gap (Dcpg) and Packerton (Dcp) Members of the Catskill Formation.
Poplar Gap Member of Catskill Formation (Devonian)
Poplar Gap Member of Catskill Formation - Gray and light-olive-gray sandstone, conglomerate, and siltstone containing intermittent red beds; laterally equivalent to Clarks Ferry, Sawmill Run, and Berry Run Members.
Pottsville Formation (Pennsylvanian)
Pottsville Formation - Predominantly gray sandstone and conglomerate; also contains thin beds of shale, claystone, limestone, and coal; includes Olean and Sharon conglomerates of northwestern Pennsylvania; thin marine limestones present in Beaver, Lawrence, and Mercer Counties; minable coals and commercially valuable high-alumina clays present locally.
Quartz fanglomerate (Triassic)
Quartz fanglomerate - Well-rounded quartzite pebbles, cobbles, and rare boulders set in a reddish-brown, sandy matrix.
Rockwell Formation (Mississippian and Devonian)
Rockwell Formation - Buff, fine- to medium-grained, crossbedded, argillaceous sandstone and dark-gray shale; includes some carbonaceous shale, sporadic conglomerate beds, and diamictite; included in lower "Pocono" of earlier workers.
Sedimentary strata at Jacksonwald and Aspers (Jurassic)
Sedimentary strata at Jacksonwald and Aspers - Arkosic sandstone; fossiliferous, gray to black shale and limestone; ripple-cross-laminated siltstone; and boulder conglomerate.
Shawangunk Formation (Silurian)
Shawangunk Formation - Light- to dark-gray, fine- to very coarse grained sandstone and conglomerate containing thin shale interbeds. Includes four members, in descending order: Tammany--conglomerate and sandstone; Lizard Creek--sandstone and red or green shale; Minsi--sandstone and conglomerate; Weiders--conglomerate. Tammany and Lizard Creek Members together are approximately equivalent to Clinton Group to the west; Minsi and Weiders Members together are equivalent to Tuscarora Formation to the west.
Spechty Kopf Formation (Mississippian and Devonian)
Spechty Kopf Formation - Light- to olive-gray, fine- to medium- grained, crossbedded sandstone, siltstone, and local polymictic diamictite, pebbly mudstone, and laminite; arranged in crude fining-upward cycles in some places; locally has grayish-red shale near top and conglomerate at base and in middle.
Stockton conglomerate (Triassic)
Stockton conglomerate - Quartz cobbles set in a poorly sorted, sandy matrix; includes conglomeratic sandstone.
Stonehenge Formation (Ordovician)
Stonehenge Formation - Medium-light-gray to medium-gray, finely crystalline, thick-bedded limestone, containing dark siliceous laminae, edgewise conglomerate beds, and fossil-fragment lenses; dolomite beds increase in number eastward.
Stonehenge Formation (Ordovician)
Stonehenge Formation - Gray, finely crystalline limestone containing dark-gray silty laminations; numerous edgewise conglomerate beds.
Stonehenge/Larke Formation (Ordovician)
Stonehenge/Larke Formation - Medium-gray, medium-bedded to laminated, fossiliferous, oolitic limestone containing edgewise conglomerate; to the west, Stonehenge is laterally equivalent to medium- to dark-gray, coarsely crystalline dolomite (Larke).
Tuscarora Formation (Silurian)
Tuscarora Formation - Light- to medium-gray quartzite and quartzitic sandstone and minor interbedded shale and siltstone, locally conglomeratic in lower part; includes (to the northwest) interbedded red and non-red sandstone (Castanea Member) at top; east of Harrisburg, equivalent to Minsi and Weiders Members of Shawangunk Formation.
Venango Formation (Devonian)
Venango Formation - Light-gray siltstone interbedded with some flaggy, gray sandstone and some bluish-gray shale; Panama Conglomerate and Woodcock Sandstone are, respectively, the lower and upper key beds defining the formation; referred to as "Cattaraugus" by some workers; includes some red shales where it interfingers to the east and south with the Catskill Formation; marine fossils present.
Waynesboro Formation (Cambrian)
Waynesboro Formation - Greenish-gray and grayish-purple shale interbedded with greenish-gray sandstone and conglomerate; occurs in Henrietta fault block only.
Weverton and Loudoun Formations, undivided (Cambrian)
Weverton and Loudoun Formations, undivided - In descending order: Weverton--gray to purplish-gray quartzite and quartzose conglomerate containing rounded pebbles. Loudoun--sericitic slate and purplish-gray, crumbly, poorly sorted, arkosic sandstone and conglomerate.
Rhode Island
Narragansett Bay Group - Dighton Conglomerate (Pennsylvanian)
Narragansett Bay Group - Dighton Conglomerate - Gray conglomerate consisting predominantly of quartz clasts set in a sand-sized matrix. Minor lenses of litharenite and arkosic sandstone.
Narragansett Bay Group - Pondville Conglomerate (Pennsylvanian)
Narragansett Bay Group - Pondville Conglomerate - Gray to greenish conglomerate with sand-sized matrix, interbedded with quartz arenite and litharenite; typically lenticular and discontinuous. At type locality (Pondville Station, Massachusetts), unit consists of interbedded red and green slate, siltstone, arkose, and quartzite-pebble conglomerate.
Narragansett Bay Group - Purgatory Conglomerate (Pennsylvanian)
Narragansett Bay Group - Purgatory Conglomerate - Buff to pale-gray conglomerate. Clasts consist entirely of quartzite; matrix primarily quartz, plus sparse amounts of magnetite. Cobbles and boulders are ubiquitously elongate, due to pressure-solution phenomena associated with deformation.
Narragansett Bay Group - Rhode Island Formation (Pennsylvanian)
Narragansett Bay Group - Rhode Island Formation - In northern Rhode Island, consists of gray to black, fine- to coarse-grained quartz arenite, litharenite, shale, and conglomerate, with minor beds of anthracite and meta-anthracite. In southern Rhode Island, consists of meta-sandstone, meta-conglomerate, schist, carbonaceous schist, and graphite. Plant fossils are common.
Narragansett Bay Group - Sachuest Arkose (Pennsylvanian)
Narragansett Bay Group - Sachuest Arkose - Gray, smoky-quartz granule-conglomerate, sandstone, and pebble to cobble conglomerate, interbedded with black carbonaceous phyllite. Includes some rock mapped formerly as Pondville Conglomerate.
Narragansett Bay Group - Wamsutta Formation (Pennsylvanian)
Narragansett Bay Group - Wamsutta Formation - Red sandstone, shale, and conglomerate, locally containing abundant volcanic detritus as clasts and matrix. Plant fossil localities occur in adjacent Massachusetts. Minor, but significant amounts of interstratified bimodal-composition volcanic lava flows consisting of alkalic basalt (locally pillowed) and rhyolite are present in adjacent Massachusetts.
Newport Group - Newport Neck Formation (Late Proterozoic? or older?)
Newport Group - Newport Neck Formation - Sequences of gray, green, and maroon graded rocks, ranging from fine-grained feldspathic granule-conglomerate to maroon slate.
Newport Group - Price Neck Formation (Late Proterozoic? or older?)
Newport Group - Price Neck Formation - Fine-grained graded beds of feldspathic siltstone and sandstone, interstratified with carbonate conglomerate, and ash-flow and lapilli tuff; some units may be lahar deposits.
South Carolina
Battleground Formation, Metasedimentary rocks, undivided (Neoproterozoic)
Battleground Formation, Metasedimentary rocks, undivided: quartz-sericite schist/phyllite and interlayered quartzite, quartz-pebble conglomerate, high-alumina quartzite, and manganiferous schist
Chatham Group, undivided (Triassic)
Chatham Group, undivided: conglomerate, sandstone and mudstone
Duplin Formation (Pliocene)
Duplin Formation: Coastal terrace of Carolinas. Pliocene equivalent to Yorktown. Deeply weathered.
South Dakota
Batesland Formation (Phanerozoic | Cenozoic | Tertiary | Miocene)
Tan to green, calcareous siltstone, claystone, channel sandstone, conglomerate, and arkose. Thickness up to 50 ft (15 m).
Greenhorn Formation, Belle Fourche Shale, Mowry Shale, Newcastle Sandstone, Skull Creek Shale, Inyan Kara Group, Morrison Formation, Unkpapa Sandstone, Sundance Formation, Spearfish Formation, Minnekahta Limestone, Opeche Shale, Minnelusa Formation, and Pahasapa Limestone (Phanerozoic | Paleozoic Mesozoic | Carboniferous Mississippian Permian(?) Triassic(?) Jurassic(?) Cretaceous-Early(?) Cretaceous-Middle(?) Cretaceous-Late)
Note: see individual unit descriptions
Hell Creek Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
Tan to brown, light- to dark-gray, "somber beds" of shale. Interbedded with brown to red carbonaceous shale, gray and brown bentonitic silty shale, and gray, brown and yellow siltstone, sandstone, and claystone-pebble conglomerate. Thickness 260-600 ft (79-183 m).
Inyan Kara Group (Phanerozoic | Mesozoic | Cretaceous-Early )
Includes: Fall River Formation- Variegated brown, red, gray to purple, calcareous, well-sorted, fine-grained sandstone, siltstone, and shale containing mica flakes. Thickness 100-200 ft (30-61 m). Lakota Formation- Yellow, brown, red-brown, gray to black silty shale, pebble conglomerate, and massive to thin-bedded, cross-bedded sandstone. Locally interbedded with fresh-water limestone and bituminous coal beds. Thickness 35-500 ft (11-152 m).
Ogallala Group (Phanerozoic | Cenozoic | Tertiary Quaternary | Miocene Pliocene(?) Pleistocene-Early)
Includes: Ash Hollow Formation- White, tan, and gray, well-cemented, calcareous sandstone and silty limestone often referred to as "mortar beds". Thickness 90-250 ft 27-76 m) Valentine Formation- Gray, unconsolidated, fine- to coarse grained, fluvial siltstone, channel sandstone, and gravel derived from western sources. Thickness 175-225 ft (53-69 m). Fort Randall Formation- Pink and gray claystone with interbedded sandstone. Also includes green to gray orthoquartzite, bentonitic clay, and conglomerate. Thickness up to 130 ft (40 m).
Pahasapa Limestone, Englewood Formation, Whitewood Limestone, Winnipeg Formation, and Deadwood Formation (Phanerozoic | Paleozoic | Cambrian Ordovician(?) Silurian(?) Devonian(?) Carboniferous Mississippian)
Note: see individual descriptions
Pierre Shale (Phanerozoic | Mesozoic | Cretaceous-Late)
Blue-gray to dark-gray, fissile to blocky shale with persistent beds of bentonite, black organic shale, or light-brown chalky shale. Contains minor sandstone, conglomerate, and abundant carbonate and ferruginous concretions. Thickness 1,000-2,700 ft (305-823 m).
Sioux Quartzite (Proterozoic | Paleoproterozoic)
Pink, reddish to tan, siliceous, fine to coarse-grained, iron-stained orthoquartzite with minor conglomerate and mudstone layers. Estimated thickness greater than 1,000 ft (305 m).
White River Group (Phanerozoic | Cenozoic | Tertiary | Eocene Oligocene)
Includes: Brule Formation (Oligocene)- White, pink, light-green, and light-brown, massive to thin-bedded, bentonitic claystone, tuffaceous siltstone, and well-bedded, calcareous, tuffaceous quartz sandstone. Thickness up to 150 ft (46 m). Chadron Formation (Eocene)- Upper beds are gray, light-brown to maroon bentonite, claystone, siltstone tuffaceous fine-grained sandstone, and local, silicified carbonate lenses. Basal portion consists of poorly cemented, white, coarse-grained arkose and conglomerate. Thickness up to 160 ft (49 m). Chamberlain Pass Formation (Eocene)- Pale olive to pale red, mottled mudstone containing white, cross-bedded channel sandstone with basal conglomerate. Thickness up to 32 ft (10 m). Slim Buttes Formation (Eocene)- White, grayish- to yellowish-orange,pale-red to pink siltstone, clayey siltstone, bentonitic claystone,medium- to fine-grained sandstone, and conglomerate. Thickness up to 48 ft (15 m).
Whitewood Limestone, Winnipeg Formation, and Deadwood Formation (Phanerozoic | Paleozoic | Cambrian Ordovician)
Whitewood Limestone (Ordovician)- Mottled, tan, gray to lavender, fine- to medium-crystalline, sparsely fossiliferous limestone and dolomite. Thickness up to 70 ft (21 m). Winnipeg Formation (Ordovician)- Grat and light-green, fissile shale, and tan, calcareous siltstone, sandy shale, and limestone lenses. Thickness up to 110 ft (34 m). Deadwood Formation (Ordovician to Cambrian)- Variegated, yellow to red, brown, gray, and green, glauconitic, conglomerate, sandstone, shale, dolomitic limestone, and dolomite. Thickness 4-400 ft (1-122 m).
Tennessee
Athens Shale (Ordovician)
Athens Shale - Medium- to dark-gray, calcareous, graptolitic shale; calcareous gray sandstone, siltstone, and locally fine-pebble quartz conglomerate; nodules of shaly limestone near base. Maximum thickness 1,500 feet.
Athens Shale (Ordovician)
Athens Shale - Medium- to dark-gray, calcareous, graptolitic shale; calcareous gray sandstone, siltstone, and locally fine-pebble quartz conglomerate; nodules of shaly limestone near base. Maximum thickness 1,500 feet.
Chilhowee Group; Cochran Conglomerate (Cambrian)
Chilhowee Gourp; Cochran Conglomerate - Quartz-pebble conglomerate, gray pebbly arkose, siltstone and shale; irregular bedding, scour features, crossbedding common; maroon micaceous arkose and shale near middle and base. Thickness about 1,200 feet.
Chilhowee Group, including Erwin Formation, Hesse Sandstone, Murray Shale, Nebo Sandstone, Nichols Shale, Cochran Conglomerate, Hampton Formation, and Unicoi Formation (Cambrian)
Chilhowee Group - Conformable sequence of dominantly clastic sediments. Thickness 3,000 to 7,500 feet; including Erwin Formation - White, vitreous quartzite, massive, with interbeds of dark-green silty and sandy shale, minor siltstone, and very fine-grained sandstone. Thickness 1,000 to 1,500 feet; Hesse Sandstone - White, vitreous quartzite, medium- to coarse-grained, occurs in massive ledges; Helenmode Member at top is gray to greenish sandstone and shale. Thickness about 600 feet; Murray Shale - Shale, silty, sandy, dull-green to brown, micaceous. Thickness about 500 feet; Nebo Sandstone - Medium-bedded, fine-grained, white, vitreous quartzite, in part feldspathic. Thickness 250 feet; Nichols Shale - Olive-gray to green, silty and sandy, micaceous shale and siltstone; local lenses of fine-grained feldspathic quartzite. Thickness about 700 feet; Cochran Conglomerate - Quartz-pebble conglomerate, gray pebbly arkose, siltstone and shale; irregular bedding, scour features, crossbedding common; maroon micaceous arkose and shale near middle and base. Thickness about 1,200 feet; Hampton Formation - Dark greenish-gray, silty and sandy, micaceous shale; numerous layers of medium-grained, feldspathic, thinly bedded sandstone. Thickness 500 to 2,000 feet; Unicoi Formation - Sequence of gray feldspathic sandstone, arkose, conglomerate, graywacke, siltstone and shale; greenish amygdaloidal basalt flows near middle and base. Thickness 2,000 to 5,000 feet.
Cochran Conglomerate (Cambrian)
Cochran Conglomerate - Quartz-pebble conglomerate, gray pebbly arkose, siltstone and shale; irregular bedding, scour features, crossbedding common; maroon micaceous arkose and shale near middle and base. Thickness about 1,200 feet.
Crab Orchard Mounatins and Gizzard Group (Pennsylvanian)
Crab Orchard Mountains and Gizzard Groups - Sandstone, conglomerate, siltstone, shale, and thin coal beds. From top down Crab Orchard Mountains group includes Rockcastle Conglomerate, Vadever Formation, Newton Sandstone, Whitwell Shale, and Sewanee Conglomerate; Gizzard Group includes Signal Point Shale, Warren Point Sandstone, and Raccoon Mountain Formation. Thickness about 1,200 to 1,400 feet.
Crab Orchard Mountains and Gizzard Groups (Pennsylvanian)
Crab Orchard Mountains and Gizzard Groups - Sandstone, conglomerate, siltstone, shale, and thin coal beds. Thickness 1,200 to 1,400 feet.
Crab Orchard Mountains Group (Pennsylvanian)
Crab Orchard Mountains Group - Only the lowest formation of the group, the Sewanee Conglomerate, is preserved in the area of this sheet. Sewanee is gray to brown, medium- to coarse-grained conglomeratic sandstone, with a thin zone of ferruginous quartz- and shale-pebble conglomerate at base. Maximum preserved thickness 35 feet.
Crab Orchard Mountains Group, including Rockcastle Conglomerate, Vandever Formation, Newton Sandstone, Whitwell Shale, and Sewanee Conglomerate (Pennsylvanian)
Crab Orchard Mountains Group - Conglomerate, sandstone, siltstone, shale, and coal; from top of Rockcastle Conglomerate to base of Sewanee Conglomerate. Thickness 200 to 950 feet; including Rockcastle Conglomerate - Conglomeratic sandstone and sandstone, gray to brown, fine- to coarse-grained. Thin coal-bearing shale locally present near middle. Thickness 150 to 220 feet; Vandever Formation - Mostly shale and siltstone, dark-gray to light-brown; conglomerate or sandstone in middle to south. Lantana and Morgan Springs coals near base and top. Thickness as much as 450 feet, average about 300 feet; Newton Sandstone - Sandstone, gray to brown or pink, fine- to medium-grained, locally conglomeratic. Thickness as much as 200 feet; average about 90 feet; Whitwell Shale - Mostly dark-gray to light-brown shale, with minor siltstone; locally middle part is sandstone. Richland coal near base; Sewanee coal in upper part. Thickness as much as 220 feet, average about 75 feet; Sewanee Conglomerate - Conglomeratic sandstone and sandstone, gray to brown, fine- to coarse-grained. Thickness as much as 200 feet, average about 100 feet.
Crooked Fork Group, including Wartburg Sandstone, Glenmary Shale, Coalfield Sandstone, Burnt Mill Shale, Crossville Sandstone, Dorton Shale (Pennsylvanian)
Crooked Fork Group - Shale, sandstone, conglomerate, siltstone, and coal; from Poplar Creek coal to top of Rockcastle Conglomerate. Thickness 320 to 455 feet; Wartburg Sandstone - Sandstone, gray to brown, fine- to medium-grained, locally conglomeratic. Poplar Creek coal and thin shale at top. Thickness 0 to 50 feet; Glenmary Shale - Mostly dark-gray to light-brown shale with minor siltstone and sandstone. Thin coal near base locally. Thickness 50 to 150 feet; Coalfield Sandstone - Sandstone, gray to brown, fine- to medium-grained. Thickness 0 to 80 feet; Burnt Mill Shale - Mostly dark-gray to light-brown shale, with minor siltstone. Thin sandstone locally present near base. Hooper coal just above base. Thickness as much as 110 feet; Crossville Sandstone - Sandstone, gray to brown or pink, fine- to medium-grained, thinly and evenly bedded. Thickness 30 to 70 feet; Dorton Shale - Mostly dark-gray to light-brown shale, with minor siltstone and sandstone. Thin coal near top. Rex coal as much as 70 feet above base. Thickness as much as 150 feet.
Gizzard Group, including Signal Point Shale, Warren Point Sandstone, and Raccoon Mountain Formation (Pennsylvanian)
Gizzard Group - Shale, siltstone, sandstone, and conglomerate; from base of Sewannee Conglomerate to top of Mississippian. Thickness 0 to 520 feet, including Signal Point Shale - Mostly dark-gray to light-brown shale, with minor siltstone. Wilder coal near top. Thickness 0 to 180 feet, average about 60 feet; Warren Point Sandstone - Sandstone and conglomeratic sandstone, gray to brown, fine- to medium-grained, locally interbedded with shale containing coal. Thickness 0 to 300 feet, thins from southeast to northwest, average thickness about 100 feet; Raccoon Mountain Formation - Shale, siltstone, and sandstone. Bon Air coal near top; White Oak and Sale Creek coals near base. Thickness 0 to 260 feet.
Grainger Formation (Mississippian)
Grainger Formation - Gray to green shale with siltstone and fine-grained glauconitic sandstone; in some areas quartz-pebble conglomerate. Thickness about 1,200 feet.
Grainger Formation (Mississippian)
Grainger Formation - Gray to green shale with siltstone and fine-grained glauconitic sandstone; in some areas quartz-pebble conglomerate. Thickness 500 to 1,000 feet.
Greasy Cove Formation and Grainger Formation (Mississippian)
Greasy Cove Formation - Gray, argillaceous limestone, calcareous shale, siltstone, and fine-grained sandstone. Equivalent to Newman Limestone. Maximum preserved thickness about 400 feet; and Grainger Formation - Gray to green shale with siltstone and fine-grained glauconitic sandstone; in some areas quartz-pebble conglomerate. Thickness about 1,200 feet.
Great Smoky Group, includes Unnamed Sandstone Unit, Anakeesta Formation, Thunderhead Sandstone, and Elkmont Sandstone (Precambrian)
Great Smoky Group - Characterized by very massive layers of coarse graywacke and arkose. The formations at right have been mapped only in region of the Great Smoky Mountains. Thickness 14,000 to about 25,000 feet; includes Unnamed Sandstone Unit - Gray, coarse sandstone and fine conglomerate, similar to Thunderhead Sandstone. Thickness about 4,500 feet; Anakeesta Formation - Dark-gray, bluish-gray, and black slate with dark-gray interbeds of fine-grained sandstone. Thickness 3,000 to 4,500 feet; Thunderhead Sandstone - Coarse, gray feldspathic sandstone, graywacke, and conglomerate; occurs in massive ledges; graded bedding and blue quartz characteristic. Thickness 5,500 to 6,300 feet; Elkmont Sandstone - Coarse to fine, gray feldspathic sandstone, graywacke, and fine conglomerate; generally finer grained beds in lower part; graded bedding typical. Thickness 1,000 to 8,000 feet.
Great Smoky Group, including Anakeesta Formation, Thunderhead Sandstone, and Elkmont Sandstone (Precambrian)
Great Smoky Group - Characterized by very massive layers of coarse graywacke and arkose. The formations have been mapped only in the region of the Great Smoky Mountains. Near Ducktown, in ascending order, the Copperhill, Hughes Gap, Hothouse, and Dean Formations are recognized. Thickness 14,000 to about 40,000 feet. Includes Anakeesta Formation - Dark-gray, bluish-gray, and black slate with dark-gray interbeds of fine-grained sandstone. Thickness 3,000 to 4,500 feet; Thunderhead Sandstone - Coarse, gray feldspathic sandstone, graywacke, and conglomerate; occurs in massive ledges; graded bedding and blue quartz characteristic. Thickness 5,500 to 6,300 feet; Elkmont Sandstone - Coarse to fine, gray feldspathic sandstone, graywacke, and fine conglomerate; generally finer grained beds in lower part; graded bedding typical. Thickness 1,000 to 8,000 feet
Lenoir Limestone (Ordovician)
Lenoir Limestone - Nodular, argillaceous, gray limestone; in places basal sedimentary breccia, conglomerate, quartz sand; Mosheim Limestone Member (dense, light- to medium-gray limestone) near base. Thickness 25 to 500 feet.
Lenoir Limestone (Ordovician)
Lenoir Limestone - Nodular, argillaceous, gray limestone; in places basal sedimentary breccia, conglomerate, quartz sand; Mosheim Limestone Member (dense, light- to medium-gray limestone) near base. Thickness 25 to 500 feet.
Maryville Limestone (Cambrian)
Maryville Limestone - Gray, ribboned (silt and dolomite), fine-grained, evenly bedded limestone; intraformational conglomerate and oolitic layers common; clay shale and light-gray dolomite locally. Thickness 300 to 800 feet.
Maryville Limestone, Rogersville Shale, Rutledge Limestone (Cambrian)
Maryville Limestone - Gray, ribboned (silt and dolomite), fine-grained, evenly bedded limestone; intraformational conglomerate and oolitic layers common; clay shale and light-gray dolomite locally. Thickness 300 to 800 feet; Rogersville Shale - Light-green, fissile clay shale; in places limestone (Craig Member) in upper part. Commonly 25 to 80 feet thick; maximum thickness 250 feet; Rutledge Limestone - Medium- to dark-gray, ribboned (silt and dolomite), medium-grained, well-bedded limestone; locally dark-gray, coarse-grained, medium-bedded dolomite in upper part. Thickness 100 to 500 feet.
Maynardville Limestone, Nolichucky Shale, Honaker Dolomite, Maryville Limestone, Rogersville Shale, Rutledge Limestone, Pumpkin Valley Shale (Cambrian)
Maynardville Limestone - Thick-bedded, bluish-gray, ribboned (silt and dolomite) nodular limestone; light-gray, fine-grained, laminated to thinly bedded, noncherty dolomite in upper part. Thickness 150 to 400 feet; Nolichucky Shale - Pastel-colored (pink, greenish, olive), flaky clay shale; gray, commonly oolitic, shaly limestone lenses; locally stromatolitic limestone layers; thin, blocky siltstone near middle. Thickness 100 feet in the east to 900 feet in the west; Honaker Dolomite - Dark-gray, medium-bedded dolomite with minor dark limestone beds; locally cherty; cryptozoans abundant in places. Thickness about 1,500 feet; Maryville Limestone - Gray, ribboned (silt and dolomite), fine-grained, evenly bedded limestone; intraformational conglomerate and oolitic layers common; clay shale and light-gray dolomite locally. Thickness 300 to 800 feet; Rogersville Shale - Light-green, fissile clay shale; in places limestone (Craig Member) in upper part. Commonly 25 to 80 feet thick; maximum thickness 250 feet; Rutledge Limestone - Medium- to dark-gray, ribboned (silt and dolomite), medium-grained, well-bedded limestone; locally dark-gray, coarse-grained, medium-bedded dolomite in upper part. Thickness 100 to 500 feet; Pumpkin Valley Shale - Dull-brown to maroon shale with numerous interbeds of thin, blocky, and sandy siltstone. Thickness 100 to 600 feet.
Middle and Lower Parts of Chickamauga Group, including Mocassin Formation, Bays Formation, Sevier Shale, Ottosee Shale, Holston Formation, Lenoir Limestone and Athens Shale (Ordovician)
Middle and Lower Parts of Chickamauga Group - A sequence of about 1,400 feet of limestone in the northeast, which thickens and becomes more clastic to the southeast and is divided into the formations shown at right. Maximum thickness about 8,000 feet. Includes Mocassin Formation - Maroon calcareous shale, siltstone, and limestone; thin metabentonite layers in upper part; mud cracks, ripple marks common. Thickness 800 to 1,000 feet; (Ob) Bays Formation - Maroon claystone and siltstone, commonly mottled greenish, evenly bedded; to northeast, light- gray to white, thick-bedded sandstone; metabentonite in upper part. Maximum thickness 1,000 feet. (Osv) Sevier Shale - Calcareous, bluish-gray shale, weathers yellowish-brown; with thin gray limestone layers; sandstone, siltstone, and locally conglomerate to the east. Thickness 2,000 to 7,000 feet; (Oo) - Ottosee Shale - Bluish-gray calcareous shale, weathers yellow; with reef lenses of coarsely crystalline reddish fossiliferous limestone ("marble"). Thickness about 1,000 feet; (Oh) - Holston Formation - Pink, gray, and red coarsely crystalline limestone (Holston Marble); in many areas upper part is sandy, crossbedded ferruginous limestone and brown to greenish calcareous shale. Thickness 200 to 600 feet; (Ol) Lenoir Limestone - Nodular, argillaceous, gray limestone; in places basal sedimentary breccia, conglomerate, quartz sand; Mosheim Limestone Member (dense, light- to medium-gray limestone) near base. Thickness 25 to 500 feet; (Oa) Athens Shale - Medium- to dark-gray, calcareous, graptolitic shale; calcareous gray sandstone, siltstone, and locally fine-pebble quartz conglomerate; nodules of shaly limestone near base. Maximum thickness 1,500 feet.
Middle and Lower parts of Chickamauga Group, including Moccassin Formation, Bays Formation, Sevier Shale, Ottosee Shale, Holston Formation, Lenoir Limestone, and Athens Shale (Ordovician)
Middle and Lower Parts of Chickamauga Group - A sequence of about 1,400 feet of limestone in the northwest part of Valley and Ridge, which thickens and becomes more clastic to the southeast and is divided into the formations shown at right. Maximum thickness about 7,000 feet. Includes Moccasin Formation - Maroon calcareous shale, siltstone, and limestone; thin metabentonite layers in upper part; mud cracks, ripple marks common. Thickness 800 to 1,000 feet;. (Ob) Bays Formation - Maroon, well-jointed claystone and siltstone, commonly mottled greenish, evenly bedded; light- gray sandstone beds and metabentonite in upper part. Maximum thickness 1,000 feet; (Osv) Sevier Shale - Calcareous, bluish-gray shale, weathers yellowish-brown; with thin, gray limestone layers; sandstone, siltstone, and locally conglomerate to the east. Thickness 2,000 to 7,000 feet; (Oo) Ottosee Shale - Bluish-gray calcareous shale, weathers yellow; with reef lenses of coarsely crystalline reddish fossiliferous limestone ("marble"). Thickness about 1,000 feet; (Oh) Holston Formation - Pink, gray, and red coarsely crystalline limestone (Holston Marble); in many areas upper part is sandy, crossbedded ferruginous limestone and brown to greenish calcareous shale. Thickness 200 to 600 feet; (Ol) Lenoir Limestone - Nodular, argillaceous, gray limestone; in places basal sedimentary breccia, conglomerate, quartz sand; Mosheim Limestone Member (dense, light- to medium-gray limestone) near base. Thickness 25 to 500 feet; (Oa) Athens Shale - Medium- to dark-gray, calcareous, graptolitic shale; calcareous gray sandstone, siltstone, and locally fine-pebble quartz conglomerate; nodules of shaly limestone near base. Maximum thickness 1,500 feet.
Ocoee Supergroup, including Walden Creek Group, (including Sandsuck Formation, Wilhite Formation, Shields Formation, Licklog Formation), Cades Sandstone, and Rich Butt Sandstone (Precambrian)
Ocoee Supergroup - Terrigenous clastic sedimentary rocks, for the most part poorly sorted and coarse. The groups are subdivided into formations only in the region of the Great Smoky Mountains. Thickness as much as 50,000 feet. Includes Walden Creek Group - The formations, other than the Sandsuck, have been mapped only in the region of the Great Smoky Mountains. Thickness about 8,000 feet; Sandsuck Formation - Olive-green and gray, argillaceous, micaceous shale with coarse feldspathic sandstone and quartz- pebble conglomerate. Thickness about 2,000 feet; Wilhite Formation - Gray to green siltstone and slate with interbeds of pebble conglomerate, sandstone, and quartzite. Thickness about 4,000 feet; Shields Formation - Massive conglomerate, sandstone, argillaceous slate; conglomerate (pebbles of various rock types) characteristic. Thickness about 1,500 feet; Licklog Formation - Feldspathic sandstone, greenish phyllite, and bluish-gray slate. Thickness about 1,500 feet; and the Cades Sandstone - Gray, well-bedded, fine- to medium-grained feldspathic metasandstone, with interbeds of dark slate and metasiltstone; precise stratigraphic position unknown. Thickness about 1,500 feet; and Rich Butt Sandstone - Gray, massive beds of feldspathic, fine- to medium-grained sandstone, with interbeds of dark slate and arkosic conglomerate; exact stratigraphic position unknown. Thickness about 1,500 feet.
Rich Butt Sandstone (Precambrian)
Rich Butt Sandstone - Gray, massive beds of feldspathic, fine- to medium-grained sandstone, with interbeds of dark slate and arkosic conglomerate; exact stratigraphic position unknown. Thickness about 1,500 feet.
Rockcastle Conglomerate (Pennsylvanian)
Rockcastle Conglomerate - Conglomeratic sandstone and sandstone, gray to brown, fine- to coarse-grained. Thin coal-bearing shale locally present near middle. Thickness 150 to 220 feet.
Sandsuck Formation (Precambrian)
Sandsuck Formation - Olive-green and gray, argillaceous, micaceous shale with coarse feldspathic sandstone and quartz- pebble conglomerate. Thickness about 2,000 feet.
Sevier Shale (Ordovician)
Sevier Shale - Calcareous, bluish-gray shale, weathers yellowish-brown; with thin, gray limestone layers; sandstone, siltstone, and locally conglomerate to the east. Thickness 2,000 to 7,000 feet.
Sevier Shale (Ordovician)
Sevier Shale - Calcareous, bluish-gray shale, weathers yellowish-brown; with thin gray limestone layers; sandstone, siltstone, and locally conglomerate to the east. Thickness 2,000 to 7,000 feet.
Unicoi Formation (Cambrian)
Unicoi Formation - Sequence of gray feldspathic sandstone, arkose, conglomerate, graywacke, siltstone and shale; greenish amygdaloidal basalt flows near middle and base. Thickness 2,000 to 5,000 feet.
Walden Creek Group, including Sandsuck Formation, Wilhite Formation, Shields Formation, and Licklog Formation (Precambrian)
The formations, other than the Sandsuck, have been mapped only in the region of the Great Smoky Mountains. Thickness about 8,000 feet. Includes Sandsuck Formation - Olive-green and gray, argillaceous, micaceous shale with coarse feldspathic sandstone and quartz- pebble conglomerate. Thickness about 2,000 feet; Wilhite Formation - Gray to green siltstone and slate with interbeds of pebble conglomerate, sandstone, and quartzite. Thickness about 4,000 feet; Shields Formation - Massive conglomerate, sandstone, argillaceous slate; conglomerate (pebbles of various rock types) characteristic. Thickness about 1,500 feet; Licklog Formation - Feldspathic sandstone, greenish phyllite, and bluish-gray slate. Thickness about 1,500 feet.
Walden Creek Group, including Sandsuck Formation, Wilhite Formation, Shields Formation, and Licklog Formation (Cambrian)
Walden Creek Group - The formations, other than the Sandsuck, are applicable mainly in the region of the Great Smoky Mountains. Thickness about 8,000 feet, Includes Sandsuck Formation - Olive-green and gray, argillaceous, micaceous shale with coarse feldspathic sandstone and quartz- pebble conglomerate. Thickness about 2,000 feet; Wilhite Formation - Gray to green siltstone and slate with interbeds of pebble conglomerate, sandstone, and quartzite. Thickness about 4,000 feet; Shields Formation - Massive conglomerate, sandstone, argillaceous slate; conglomerate (pebbles of various rock types) characteristic. Thickness about 1,500 feet.; Licklog Formation - Feldspathic sandstone, greenish phyllite, and bluish-gray slate. Thickness about 1,500 feet.
Walden Creek Group; Sandsuck Formation (Precambrian)
Wladen Creek Group; Sandsuck Formation - Olive-green and gray, argillaceous, micaceous shale with coarse feldspathic sandstone and quartz- pebble conglomerate. Thickness about 2,000 feet.
Texas
Allamore Formation (preCambrian-Proterozoic [Grenville])
Allamore Formation
Antlers Sand (Phanerozoic | Mesozoic | Cretaceous-Early)
Antlers Sand
Archer City Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Archer City Formation
Bissett Conglomerate (Phanerozoic | Mesozoic | Cretaceous-Early)
Bissett Conglomerate
bolson deposits (Phanerozoic | Cenozoic | Tertiary | Pliocene)
bolson deposits
Brazos River Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian [Des Moines])
Brazos River Formation
Brushy Canyon Formation (Phanerozoic | Paleozoic | Permian [Guadalupe])
Brushy Canyon Formation
Catahoula Formation (Phanerozoic | Cenozoic | Tertiary | Oligocene)
Catahoula Formation
Catahoula Formation and Frio Clay, undivided (Phanerozoic | Cenozoic | Tertiary | Oligocene)
Catahoula Formation and Frio Clay, undivided
Cathederal Mountain Formation (Phanerozoic | Paleozoic | Permian [Leonard])
Cathederal Mountain Formation
Chisos Formation of Schiebout et al (1987) and the Big Yellow Sandstone Member of their Tornillo Formation, undivided (Phanerozoic | Cenozoic | Tertiary | Eocene Oligocene)
Chisos Formation of Schiebout et al (1987) and the Big Yellow Sandstone Member of their Tornillo Formation, undivided
Delaho and Rawls Formations, undivided (Phanerozoic | Cenozoic | Tertiary | Oligocene Miocene)
Delaho and Rawls Formations, undivided NOTE: This unit is represented within the map unit explanation of (Geol. Map of Texas, 1992, Bur. Econ. Geol.) but does not occur on the map and is NOT included in the spatial data.
Delaho Formation and unit 9 of Rawls Formation (Phanerozoic | Cenozoic | Tertiary | Miocene)
Delaho Formation and unit 9 of Rawls Formation NOTE: This unit is represented within the map unit explanation of (Geol. Map of Texas, 1992, Bur. Econ. Geol.) but does not occur on the map and is NOT included in the spatial data.
Dockum Group, undivided (Phanerozoic | Mesozoic | Triassic-Late)
Dockum Group
Duff Formation, Decie Member from Paisano caldera (Phanerozoic | Cenozoic | Tertiary | Oligocene-Early)
Duff Formation, Decie Member from Paisano caldera
Duff Formation (with Decie Member from Paisano caldera shown separately), Cottonwood Springs Basalt, Potato Hill Andesite, Sheep Canyon Basalt, Crossen Trachyte, and Pruett Formation, undivided (Phanerozoic | Cenozoic | Tertiary | Eocene-Late Oligocene-Early)
Duff Formation (with Decie Member from Paisano caldera shown separaetly), Cottonwood Springs Basalt, Potato Hill Andesite, Sheep Canyon Basalt, Crossen Trachyte, and Pruett Formation, undivided
Eagle Mountains caldera volcanic rocks (Phanerozoic | Cenozoic | Tertiary | Oligocene)
Eagle Mountains caldera volcanic rocks
El Paso Formation and Bliss Sandstone, undivided (Phanerozoic | Paleozoic| Cambrian-Furongian(?) Ordovician-Early)
El Paso Formation and Bliss Sandstone, undivided
Etholen Conglomerate (Phanerozoic | Mesozoic | Cretaceous-Early)
Etholen Conglomerate
Gaptank Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early Pennsylvanian-Middle Pennsylvanian-Late)
Gaptank Formation
Gatuna Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Middle(?))
Gatuna Formation
Glen Rose Limestone (Phanerozoic | Mesozoic | Cretaceous-Early)
Glen Rose Limestone
Goliad Formation (Phanerozoic | Cenozoic | Tertiary | Miocene)
Goliad Formation
Hannold Hill Member of Tornillo Formation (Phanerozoic | Cenozoic | Tertiary | Eocene)
Hannold Hill Member of Tornillo Formation
Haymond Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early)
Haymond Formation
Hazel Formation (preCambrian-Proterozoic [Grenville])
Hazel Formation
Hensell Sand (Phanerozoic | Mesozoic | Cretaceous-Early [Comanchean)
Hensell Sand
Hickory Sandstone Member (Phanerozoic | Paleozoic | Cambrian-Middle)
Hickory Sandstone Member
Hueco Limestone (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Hueco Limestone
Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation (Phanerozoic | Cenozoic | Tertiary | Eocene-Late)
Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation
Lenox Hills and Neal Ranch Formations, undivided (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Lenox Hills and Neal Ranch Formations, undivided
Malone Formation (Phanerozoic | Mesozoic | Jurassic-Late)
Malone Formation
Markley Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
Markley Formation
Mineral Wells Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian [Missouri])
Mineral Wells Formation
Mundy Breccia and Castner Limestone, undivided (preCambrian-Proterozoic)
Mundy Breccia and Castner Limestone, undivided
Nocona Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp Leonard])
Nocona Formation
Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation (Phanerozoic | Cenozoic | Tertiary | Oligocene)
Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation
Presidio Formation (Phanerozoic | Mesozoic | Cretaceous-Early [Aptian Albian])
Presidio Formation
Quaternary-Tertiary bolson deposits (Phanerozoic | Cenozoic | Tertiary Quaternary | Pliocene Pleistocene)
Quaternary-Tertiary bolson deposits
Quaternary-Tertiary deposits, undivided (Phanerozoic | Cenozoic | Tertiary Quaternary | Pliocene Pleistocene)
Quaternary-Tertiary deposits, undivided
Skinner Ranch and Hess Formations, undivided (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Skinner Ranch and Hess Formations, undivided
Smithwick Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Atoka])
Smithwick Formation
Strawn Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Atoka Des Moines])
Strawn Group
Tesnus Formation (Phanerozoic | Paleozoic | Carboniferous Mississippian-Late Pennsylvanian-Early)
Tesnus Formation
Thrifty and Graham Formations, undivided (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Virgil])
Thrifty and Graham Formations, undivided
Travis Peak Formation (Phanerozoic | Mesozoic | Cretaceous-Early)
Travis Peak Formation
Twin Mountains Formation (Phanerozoic | Mesozoic | Cretaceous-Early)
Twin Mountains Formation
Van Horn Sandstone (preCambrian-Proterozoic [Grenville])
Van Horn Sandstone
Vieja Group, including Bracks Rhyolite, Chambers and Colmena Tuffs and Gill Breccia (Phanerozoic | Cenozoic | Tertiary | Eocene Oligocene)
Vieja Group, including Bracks Rhyolite, Chambers and Colmena Tuffs and Gill Breccia
Waggoner Ranch Formation (Phanerozoic | Paleozoic | Permian [Leonard])
Waggoner Ranch Formation
Whitehorse Group and Blaine Formation, undivided (Phanerozoic | Paleozoic | Permian [Guadalupe])
Whitehorse Group and Blaine Formation, undivided
Wilberns Formation showing Point Peak, Morgan Creek Limestone, and Welge Sandstone Members, undivided (Phanerozoic | Paleozoic | Cambrian-Furongian)
Wilberns Formation showing Point Peak, Morgan Creek Limestone, and Welge Sandstone Members, undivided
Wilke Ranch Formation (Phanerozoic | Paleozoic | Permian [Leonard])
Wilke Ranch Formation
Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided (Phanerozoic | Paleozoic| Cambrian Ordovician)
Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided
Yearwood Formation (Phanerozoic | Mesozoic | Cretaceous-Early)
Yearwood Formation
Yucca Formation (Phanerozoic | Mesozoic | Cretaceous-Early)
Yucca Formation
Utah
Cambrian quartzite in central Utah (Early to Middle Cambrian)
Cambrian quartzite in Logan-Huntsville Allochthon (Early to Middle Cambrian)
Cambrian quartzite in Salt Lake City-Coalville-Randolph region (Early to Middle Cambrian)
Cambrian quartzite in Uinta Mountains-Uinta Basin area (Early to Middle Cambrian)
Cambrian quartzite in western Utah (Early Cambrian)
Cretaceous (1) sedimentary rocks in southwestern Utah (Late Cretaceous)
Cretaceous (2) sedimentary rocks in central Utah (Cretaceous)
Cretaceous (2) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Late Cretaceous)
Cretaceous (2) sedimentary rocks in western Utah (Late Cretaceous)
Cretaceous (3) sedimentary rocks in central Utah (Late Cretaceous)
Cretaceous (3) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Late Cretaceous)
Cretaceous (3) sedimentary rocks in western Utah (Late Cretaceous)
Cretaceous and Tertiary sedimentary rocks in central Utah (Late Cretaceous to Eocene)
Cretaceous and Tertiary sedimentary rocks in southeastern Utah (Late Cretaceous to Paleocene)
Cretaceous and Tertiary sedimentary rocks in Uinta Mountains-Uinta Basin region (Late Cretaceous to Paleocene)
Jurassic (2) sedimentary rocks in central Utah (Late Jurassic)
Jurassic (2) sedimentary rocks in southeastern Utah (Late Jurassic)
Jurassic (2) sedimentary rocks in Uinta Mountains-Uinta Basin region (Late Jurassic)
Ordovician sedimentary rocks in Logan-Huntsville Allochthon (Ordovician)
Tertiary (1) sedimentary rocks in Logan-Huntsville Allochthon (Late Cretaceous to Early Eocene)
Tertiary (1) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Late Paleocene to Early Eocene)
Tertiary (1) sedimentary rocks in southwestern Utah (Late Paleocene to Early Oligocene)
Tertiary (2) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Eocene)
Tertiary (3) sedimentary rocks in central Utah (Late Eocene to Early Oligocene)
Tertiary (4) sedimentary rocks in northwestern Utah (Middle Miocene to Late Pliocene)
Tertiary (4) sedimentary rocks in southwestern Utah (Miocene)
Tertiary (4) sedimentary rocks in Uinta Mountains-Uinta Basin region (Oligocene)
Tertiary (5) sedimentary rocks in southeastern Utah (Pliocene)
Tertiary (5) sedimentary rocks in southwestern Utah (Miocene to Pliocene)
Tertiary (5) sedimentary rocks in Uinta Mountains-Uinta Basin region (Miocene)
Triassic (1) sedimentary rocks in Salt southeastern Utah (Early Triassic)
Triassic (1) sedimentary rocks in Salt southwestern Utah (Early Triassic)
Triassic (2) sedimentary rocks in central Utah (Middle to Late Triassic)
Triassic (2) sedimentary rocks in Logan-Huntsville Allochthon (Middle to Late Triassic)
Triassic (2) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Middle to Late Triassic)
Triassic (2) sedimentary rocks in southeastern Utah (Late Triassic)
Triassic (2) sedimentary rocks in southwestern Utah (Late Triassic)
Triassic (2) sedimentary rocks in Uinta Mountains-Uinta Basin region (Late Triassic)
Triassic (2) sedimentary rocks in western Utah (Late Triassic)
Younger Precambrian metamorphic rocks in central Utah (Proterozoic Z)
Younger Precambrian metamorphic rocks in Logan-Huntsville Allochthon (Proterozoic Z)
Younger Precambrian metamorphic rocks in Uinta Mountains-Uinta Basin region (Proterozoic Y)
Younger Precambrian metamorphic rocks in western Utah (Precambrian)
Virginia
Buffards Formation (Ordovician)
Buffards Formation - Micaceous conglomerate, schist, and phyllite.
Chemung Formation (redefined as Foreknobs Formation) (Devonian)
Chemung Formation - Shale and sandstone with a few thin, quartz-pebble conglomerates and red-beds.
Chilhowee Group (Cambrian)
Chilhowee Group - Appalachian Plateaus and Valley and Ridge: Quartzite, conglomerate, feldspathic sandstone, phyllite, and minor ferruginous sandstone and volcanic rocks. Blue Ridge Anticlinorium: Conglomerate, quartzite, metasiltstone, and phyllite.
Fauquier Formation - Metaconglomerate (Proterozoic Z)
Fauquier Formation - Pebble or cobble conglomerate.
Hancock, Rose Hill, and Clinch Formations (Silurian)
Hancock, Rose Hill, and Clinch Formations - Limestone and dolomite; dusky-red and green shale and sandstone; and sandstone, shale and conglomerate.
Knobs Formation, Paperville Shale, Lenoir and Mosheim Limestone (Ordovician)
Knobs Formation, Paperville Shale, Lenoir and Mosheim Limestone - Sandstone, conglomerate, siltstone; black, fissile shale; and limestone, in part cherty.
Lee Formation (Pennsylvanian - Mississippian)
Lee Formation - Quartzarenite, sandstone, conglomerate, shale, siltstone, and coal.
Lee Formation (Pennsylvanian)
Lee Formation - Quartzarenite, sandstone, conglomerate, shale, siltstone, and coal.
Lynchburg Group - Conglomerate and metagraywacke (Proterozoic Z)
Lynchburg Group - Conglomerate and metagraywacke.
Lynchburg Group - Fanglomerate (Proterozoic Z)
Lynchburg Group - Fanglomerate
Lynchburg Group; Metagraywacke (Proterozoic Z)
Lynchburg Group - Metagraywacke
Massanutten Sandstone (Silurian)
Massanutten Sandstone - Quartzarenite with lenses of conglomerate.
Mississippian Formations Undivided (Mississippian)
Mississippian Formations Undivided - Includes Pennington Group, Bluefield Formation, Greenbrier Limestone, Maccrady Shale and Price Formation; Includes Newman Limestone, Fort Payne Chert, and Grainger Formation in western Lee County
Mount Rogers Formation - Conglomerate, graywacke, laminated siltstone, and shale. (Proterozoic Z)
Mount Rogers Formation - Conglomerate, graywacke, laminated siltstone, and shale.
Newark Supergroup; Conglomerate, arkosic maatrix (Upper Triassic)
Conglomerate, arkosic matrix
Newark Supergroup; Conglomerate, carbonate clasts (Upper Triassic)
Conglomerate, carbonate clasts
Newark Supergroup; Conglomerate, greenstone clasts (Upper Triassic)
Conglomerate, greenstone clasts
Newark Supergroup; Conglomerate, mixed clasts (Upper Triassic)
Conglomerate, mixed clasts
Newark Supergroup; Jurassic Conglomerate (Lower Jurassic)
Conglomerate
Norton, New River, Lee and Pocahontas Formations Undivided (Pennsylvanian)
Norton, New River, Lee and Pocahontas Formations Undivided - Norton Formation: siltstone, shale, sandstone, and coal. New River Formation: Sandstone siltstone, shale, coal. Pocahontas Formation: Sandstone, siltstone, shale, and coal. Lee Formation: Quart
Pennington Group (Mississippian)
Pennington Group - Shale, sandstone, dusky-red mudstone, conglomerate, siltstone, and limestone.
Price Formation (Mississippian)
Price Formation - Sandstone, conglomeratic sandstone, and shale with carbonaceous partings and impure coal beds.
Silurian Formations Undivided (Silurian)
Silurian Formations Undivided - Some landslides with intact stratigraphic units in Giles County area. Includes: Dsu, Skrt, Sm. (Shrc?)
Swift Run Formation (Proterozoic Z)
Swift Run Formation - Phyllite, metasandstone, and metaconglomerate.
Unicoi Formation (Cambrian)
Unicoi Formation - Sandstone and quartzite with phyllite, tuffaceous phyllite, conglomerate, and minor basalt.
Vermont
Bridgeman Hill Formation (Cambrian)
Bridgeman Hill Formation - Undifferentiated dolomite, slate, and conglomerate, on east limb of St. Albans synclinorium, about equivalent to Dunham, Parker, Rugg Brook, and Saxe Brook Formations.
Cheshire Quartzite (Cambrian)
Cheshire Quartzite - Very massive, white to faintly pink or buff vitreous quartzite near the top in west-central and southwestern VT; predominantly a less massive appearing mottled gray, somewhat phyllitic quartzite; dolomitic sandstone and conglomerate near the base of the formation in west-central VT apparently grades southward into the Dalton Formation. Mapping in Bristol Notch and along the Green Mountain front indicate that the Cheshire Quartzite appears to be at least 2500 ft thick, which is about 2.5 times the original estimated thickness to the north and south. Near the base, the Cheshire is a massive argillaceous feldspathic meta-sandstone, containing recrystallized quartz and K-feldspar in a muscovite and biotite matrix. These lithologies grade upward through medium to thick-bedded schistose feldspathic meta-sandstones to clean, massive 'quartzites' of the Green Mountain front. Rocks currently mapped as the eastern-most Cheshire Quartzite probably belong to the Pinnacle Formation and are in fault contact with the Cheshire (Condon, 1993).
Clarendon Springs, Ticonderoga, and Rock River Dolomites; Gorge Formation (Cambrian)
Clarendon Springs, Ticonderoga, and Rock River Dolomite; Gorge Formation - Fairly uniform, massive, smooth weathered gray dolomite characterized by numerous geodes and knots of white quartz; quartz sandstone and irregular masses of chert are near the top. Called the Ticonderoga west of Orwell and Champlain thrusts and the Rock River east of Philipsburg thrust. The Gorge is a partly conglomeratic facies on the west limb of the St. Albans synclinorium..
Clough Formation (Silurian)
Clough Formation - Quartzite, quartz-conglomerate, and mica schist; lenses of fossiliferous calcareous quartzite in upper part. (Southeastern Vermont).
Clough Formation (Silurian)
Clough Formation - Boulders, cobbles, pebbles and angular fragments of quartzite, micaceous quartzite, and gray mica schist in matrix of dark gray quartz-mica schist or quartzite; schist commonly contains porphyroblasts of biotite, less commonly garnet. (Northeastern Vermont).
Dalton Formation (Cambrian)
Dalton Formation - Schistose quartzite containing pebbles of feldspar and blue quartz; impure dolomite containing pebbles of quartz and feldspar occurs locally; conglomerate common near base. Occurs in southwestern Vertmont.
Highgate Formation (Ordovician)
Highgate Formation - Banded blue limestone and calcareous slate; local lenses of limestone conglomerate; on west limb of St. Albans synclinorium.
Hortonville, or Cumberland Head, and Glens Falls Formations, Undifferentiated (Ordovician)
Hortonville, or Cumberland Head, and Glens Falls Formations, Undifferentiated - Hortonville or Cumberland Head is combined with Glens Falls where the boundary with the Glens Falls is widely covered by surficial deposits, also where the Cumberland Head thins.
Missisquoi Formation, Umbrella Hill Member (Ordovician)
Missisquoi Formation, Umbrella Hill Member - Quartz and slate pebble phyllitic conglomerate with interbeds of slate and phyllite - chiefly quartz-sericite-magnetite-chloritoid rocks.
Morses Line Formation (Ordovician)
Morses Line Formation - Calcareous and non-calcareous slate; local lenses of thin-bedded limestone, limestone conglomerate, and dolomite; in St. Albans synclinorium.
Mount Hamilton Formation (Ordovician)
Mount Hamilton Formation - White weatherd black, gray, green, purple, and red hard slates, some interbedded with thin cherty appearing quartzites and ribbon limestones a few vinches apart; smooth, soft, red slate; beds of ankeritic quartzite a few inches to several feet thick, locally containg layers of edgewise conglomerate; and a polymict limestone conglomerate. Lithic features vary laterally and are in many places indistinguishable from those of the underlying Hatch Hill and West Castleton Formations.
Ottauquechee Formation (Cambrian)
Ottauquechee Formation - Black carbonaceous phyllite or schist containing interbeds of massive quartzite commonly criss-crossed by veins of white quartz; quartzite is dark gray and carbonaceous, light gray, or white; also includes light green quartz-sericite-chlorite phyllite or schist and sercitic quartzite; beds of phyllitic graywacke and feldspar granule conglomerate are north of Lamoille River. Schist contains abundant porphyroblasts of garnet and biotite from Ludlow south. The Ottauquechee contains two major units: A black phyllite and the Thatcher Brook Member. The black phyllite contains a previously unreported sub-unit of gray carbonate schist. The Thatcher Brook Member (named in an abstract by Armstrong and others, 1988) is a carbonaceous albitic schist with greenstones and ultramafics. These rocks have previously been included in the Ottauquechee but have never been differentiated from the black phyllite. Member is in fault contact with the silvery green schist of the Pinney Hollow Formation to the west. Age is Cambrian (Ratcliff, in press).
Pinnacle Formation (Cambrian)
Pinnacle Formation - Schistose graywacke, gray to buff, commonly striped, quartz-albite-sericite-biotite-chlorite rock predominates; quartz-cobble and boulder conglomerate is common, chiefly near base. (Northern and Central Vermont).
Rugg Brook Formation (Cambrian)
Rugg Brook Formation - Sandy gray dolomite, dolomite conglomerate, and interbeds of gray-weathered sandstone, in St. Albans and Middlebury synclinoria.
Shaw Mountain Formation (Silurian)
Shaw Mountain Formation - Quartzite, quartz conglomerate, cummingtonite schist, amphibolite, and quartz-sericite schist with porphyroblasts of biotite and garnet.
Shaw Mountain Formation (Silurian)
Shaw Mountain Formation - Chiefly tan to brown weathered quartzose limestone and calcareous quartzite characterized by specks of limonite after ankerite; locally underlain by quartz conglomerate and overlain by blue fossiliferous crystalline limestone; greenstone and quartz-sericite schist.
Sweetsburg Formation, Rockledge Conglomerate Member (Cambrian)
Sweetsburg Formation, Rockledge Conglomerate Member - Phenoclasts chiefly of biohermal limestone in a matrix of gray limestone containing frosted quartz sand grains.
Sweetsburg Formation, Skeels Corners Slate and Mill River Conglomerate Members Undifferentiated (Cambrian)
Sweetsburg Formation, Skeels Corners Slate and Mill River Conglomerate Members Undifferentiated - Black slate; local dolomite, sandstone, dolomite conglomerate, limestone bioherm, limestone, and calcareous shale. The Mill River is a basal limestone conglomerate.
Tyson Formation (Cambrian)
Tyson Formation - Feldspathic quartz-mica schist containing biotite, chlorite, and carbonate; many beds contain pebbles of quartz and feldspar; cobble or boulder conglomerate commonly at base; thin beds of quartzite, carbonaceous phyllite, and schistose dolomite in upper part, overlain at top by massive buff dolomite as much as 30 ft thick. (Southern and Central Vermont). The Tyson Formation contains grits and conglomerates at its base that unconformably overlie basement. The conglomerates and grits are as much as 150 m thick and contain lenses of dolomitic quartzite and feldspathic grit. Unit also contains black carbonaceous phyllite and interbedded dolostone as much as 100 m thick, followed by beige to tan weathering beds of dolostone that increase in abundance toward the top of the unit and pass into punky weathering dolomitic and feldspathic quartzite at the top. From a point near the southwest corner of the Andover quad, the rocks of the Tyson Formation are laterally replaced by albitic schists and granofels of the Hoosac Formation to the south. Therefore, Tyson laterally replaces the Hoosac from south to north along the eastern margin of the Green Mountain massif. The Tyson Formation is of Late Proterozoic(?) and Early Cambrian age (Ratcliffe, 1994).
Washington
Cambrian limestone and dolomite (Early Cambrian-Middle Ordovician)
Mostly massive dolomite, with a basal unit of gray to dark-gray limestone interbedded with limy shale, and an upper unit of fine-grained massive limestone with some marble; Pend Oreille and northern and central Stevens Counties. Three-fold division less evident in Colville area. Dolomite, with minor basal unit of interbedded limestone and phyllite in the Addy-Dunn Mountain area of Stevens County. Marble, dolomite, limestone, and limy slate in Hunters' district. Dolomitic marble in southern Stevens and northern Lincoln Counties. Middle Cambrian fossils near base in Metaline district, and Bathyuriscus-Elrathina fauna in lower unit in Leadpoint district. Phosphatic brachiopods in upper unit in Leadpoint district tentatively assigned to Middle and Upper Cambrian.
Cambrian quartzite (Cambrian)
Gritstone with conglomerate in lower part and gray, white, and buff platy quartzite in upper part grading upward into phyllite; northern Pend Oreille County. Light-gray, platy, medium- to thick-bedded quartzite in upper part and darker impure quartzite with some interbedded argillite or phyllite in lower part; north-central Stevens County. White, gray, and reddish, medium- to thick-bedded quartzite in lower part and thin interbeds of quartzite and argillite in upper part, with very low Lower Cambrian fossils (Nevadia, Hyolthellus, and three genera of brachipods) near base of upper part; Addy district of central Stevens County. Thick argillite and thin quartzite units form an uppermost zone in southwestern Stevens County. Conspicuous phyllite units near base in north-central Lincoln County.
Carboniferous and Permian volcanic rocks (Devonian to Permian; Triassic in Asotin County)
Predominantly altered andesite, basalt, and diabase with interbedded chert and argillite; includes some tuff, greenstone, and spilitic volcanic rocks; northern Cascade Mountains. Mostly schistose greenstone, some agglomerate, and rarely lapilli; includes minor beds of limestone with associated argillite and graywacke; northwestern Stevens County.
Carboniferous-Permian sedimentary and volcanic rocks (Devonian to Permian, minor Mesozoic)
Predominantly sedimentary rocks. Graywacke, argillite, and slate; includes minor marble, siltstone, arkose, conglomerate, ribbon cherts, and volcanic rocks. Some Devonian rocks may be included in northwestern Washington.
Carboniferous-Permian sedimentary and volcanic rocks (Devonian to Permian; some Jurassic)
Sedimentary and volcanic rocks, undivided. Cherty and slaty argillite, siltstone, graywacke, chert, greenstone, tuff, andesite, and spilitic volcanics.
Carboniferous rocks (Late Devonian to Mississippian)
Thin-bedded graywacke, shale, argillite, slate, schist, volcanic breccia, gritstone, conglomerate, and limestone on northeast shore of Orcas Island. Limestone or dolomitic limestone, apparently interbedded with limy argillite and graywacke, forms belt of small separate outcrops between Springdale and Valley in southeastern Stevens County. Late Devonian to Early Pennsylvanian in age.
Cretaceous nonmarine rocks (Late Cretaceous)
Redbeds of thick-bedded sandstone, shale, and pebble conglomerate in upper Methow River area of Okanogan County.
Cretaceous sedimentary rocks, mostly marine (Late Cretaceous; possibly Eocene)
Cretaceous conglomerate, sandstone, shale, breccia, limestone, and gritstone in San Juan Islands.
Cretaceous sedimentary rocks, mostly marine (Cretaceous)
Lower Cretaceous greenish-gray massive arkosic sandstone and light-gray sandy shale in western Okanogan County. Includes phyllite in eastern Whatcom County.
Cretaceous sedimentary rocks, mostly marine (Cretaceous)
Upper Cretaceous black siltstone, graywacke, and silica pebble conglomerate in western Okanogan County.
Eocene nonmarine rocks (Eocene)
Predominantly sandstone and shale. Includes some conglomerate in the Cle Elum area in Kittilas County. Contains extensive coal seams near Roslyn and carbonaceous shale and coal beds in White Pass area. Contains tuff beds in northwestern Ferry County.
Eocene volcanic rocks (Eocene )
Predominantly andesite flows and breccia; includes interbedded sedimentary rocks south of Startup in Snohomish and King Counties.
Lower Tertiary volcanic rocks, undivided (Eocene)
Predominantly andesite flows and flow breccia; includes basalt flows, minor rhyolitic rocks, and some sedimentary rocks.
Lower upper Eocene marine and nonmarine rocks (Eocene)
Predominantly massive to well-bedded tuffaceous marine siltstone with interbedded arkosic and basaltic sandstone. Includes conglomerate in King County and along north side of Olympic Peninsula. Minor lava flows and breccia in western Lewis County and eastern Grays Harbor County. Coal seams in central Lewis County and north-central Pierce County.
Mesozoic-Tertiary marine rocks, undivided (Miocene to Eocene)
Dark-gray, massive to poorly bedded gray-wacke of the interior Olympic Peninsula; commonly with interbedded slate, argillite, volcanic rocks, and minor arkosic sandstone. Includes rocks both older and younger than Ev2, some of which may be Paleozoic.
Mesozoic volcanic rocks, undivided (Jurassic)
Includes latite, andesite and basalt flows, tuff, and agglomerate. Interbedded sedimentary rocks in Orient area of Stevens County.
Miocene marine rocks (Miocene)
Massive to thin-bedded, friable, basaltic to feldspathic sandstone, with shale, siltstone, and local pebble conglomerate interbeds.
Miocene nonmarine rocks (Late Miocene)
Poorly to moderately consolidated tuffaceous sandstone, conglomerate, siltstone, and claystone in western Washington. Chiefly clay and shale with minor sand, gravel, and diatomaceous earth near Spokane. Includes diatomite beds near Yakima and Quincy, and some marine beds in Western Washington.
Miocene-Pliocene marine rocks (Miocene-Pliocene)
Brown-gray, coarse-grained, moderately consolidated, commonly cross-bedded sandstone. Grades locally into gritstone and conglomerate lenses; includes minor shale beds; sandstone often shaly and in some areas grades into claystone.
Miocene-Pliocene nonmarine rocks (Miocene-Pliocene)
Tuffaceous and pumiceous andesitic sandstone and siltstone with interbedded conglomerate and claystone. Conglomerate beds chiefly andesitic, but also quartzitic, granitic, and basaltic; includes basalt flows locally.
Miocene-Pliocene volcanic rocks (Miocene-Pliocene)
Dark-gray, fine-grained, dense, porphyritic in part, basalt flows in central and south-central part of State; commonly interbedded with conglomerate, sandstone, and siltstone. Includes small areas of rhyolite north of Cle Elum in Kittitas County, and andesite north of Leavenworth in Chelan County.
Miocene volcanic rocks (Middle Miocene)
Dark-gray to black, dense aphanitic basalt flows; commonly columnar jointed, less commonly irregularly and platy jointed; some flows vesicular, grading to scoriaceous; includes minor pillow lava, palagonite beds, and interbedded soil profiles and sedimentary beds; contains diatomite beds locally. Maximum thickness in south-central Washington may be in excess of 10,000 feet; much thinner in western Washington, where flows are mostly associated with marine sedimentary rocks. Includes acidic and intermediate volcanic rocks in northern Cascade Mountains.
Oligocene marine rocks (Late Eocene to Late Oligocene)
Massive, tuffaceous and nontuffaceous sandstone and siltstone; locally concretionary; includes conglomerate along the north coast of Olympic Peninsula and basaltic sandstone east of Chehalis.
Oligocene-Miocene marine rocks (Oligocene)
Massive to thin-bedded, coarse-grained sandstone, conglomerate, conglomeratic sandstone, shale, and sandy shale.
Oligocene-Miocene volcanic rocks (Miocene)
Andesite flow breccia, andesite flows, and minor tuff beds; includes some basalt flows and flow breccia. Commonly more massive and less altered than similar-appearing Eocene-Oligocene volcanic rocks. Clastic flows and flows of black glass, and course to fine-grained clastic and pyroclastic rocks in the Republic and Curlew areas of Ferry County.
Oligocene nonmarine rocks (Oligocene)
Andesite conglomerate, tuff beds, and mudflow material. Includes some interbedded andesite flows in Columbia River Gorge. Lake sediments with Oligocene flora in Republic area in Ferry County. Massive tuffaceous sandstone and siltstone with beds of coal and high-alumina clay in Castle Rock-Toledo coal district in Cowlitz and Lewis Counties; include local interbedded basalt flows and some marine and late Eocene rocks.
Oligocene volcanic rocks (Oligocene)
Andesite and rhyodacite flows, tuff, and tuffaceous sandstones of northern Lincoln County and southwestern Stevens County.
Paleocene-Cretaceous nonmarine rocks (Eocene (see age coding))
Brown-gray to light-gray, medium- to course-grained massive cross-bedded arkose with interbedded conglomerate and siltstone. Contains several coal seams in Whatcom County. Iron-rich laterite at base near Cle Elum and Blewett Pass in Kittitas and Chelan Counties.
Permian rocks (Permian-Triassic)
Conglomerate, graywacke, siltstone, argillite and interbedded fossiliferous limestone, greenstone, and minor angular conglomerate in northwestern Stevens and Ferry Counties. Impure quartzite, sandstone, graywacke, greenstone, ribbon chert, chert breccia, and limestone in Snohomish County and on San Juan Island. Lower Permian limestone on Black Mountain in northwestern Whatcom County. Middle Permian rocks in northeastern Washington.
Pliocene marine rocks (Pliocene)
Coarse conglomerate, shale, and minor sandstone; along ocean beaches in Grays Harbor County.
Pliocene nonmarine rocks (Pliocene)
Conglomerate, sandstone, shale, and mudstone. Tuffaceous in part; contains alluvial fan type material locally.
Precambrian conglomerate (Late-Proterozoic)
Gray-brown, coarse, poorly sorted pebbles and cobbles of limestone, dolomite, reddish-brown quartzite, black slate or phyllite, and rarely granitic rocks in a gray sandy phyllite matrix; northeastern Pend Oreille County and southwestern Stevens County. Rocks become finer grained and more schistose and the unit becomes thicker toward the southwest, where there is included an isolated subunit which may be a tillite, consisting of cobbles, boulders, and blocks of argillite and carbonate rocks in a fine silty matrix.
Precambrian (?) phyllite (Cambrian-Precambrian boundary)
Mostly phyllite with interbedded carbonate rocks, quartzite, and gritstone; some tufflike beds and conglomerate at the base. Rocks confined to northeastern Pend Oreille County and central Stevens County.
Precambrian volcanic rocks (Late-Proterozoic)
Mostly homogenous schistose greenstone; in places massive, mottled, and containing conspicuous calcite and epidote. Tuffaceous chlorite schist in upper part in northern Pend Oreille County. Amphibolite and plagioclase amphibolite in Little Pend Oreille Lakes district. Massive to sheared or schistose greenstone with dark-green ovoid spots; agglomeratic and amygodaloidal in places; sheared pillows near Blue Creek, central Stevens County; minor intrusive phase and probable center of eruption west of Finch magnesite quarry; central to southwestern Stevens County.
Pre-Middle Jurassic sedimentary and volcanic rocks (Jurassic)
Predominantly sedimentary rocks. Graywacke, argillite, and slate; includes minor marble, siltstone, arkose, conglomerate, ribbon cherts, and volcanic rocks.
Pre-Middle Jurassic sedimentary and volcanic rocks (Late Paleozoic deposition? with Cretaceous metamorphism?)
Sedimentary and volcanic rocks, undivided. Graywacke, argillite, slate, greenstone, and spilitic volcanic rocks.
Pre-upper Eocene rocks (Eocene (Olympic Peninsula); Cretaceous(?) (Yakima County))
Argillite and graywacke between inner and outer volcanic belts in Olympic Peninsula. Sheared carbonaceous argillite, argillite, graywacke, and minor conglomerate lenses and altered lava flows in western Yakima County.
Pre-Upper Jurassic metamorphic rocks of the low-grade zone (Jurassic)
Greenschist, phyllite, and slate; includes some limestone, quartzose phyllite, schistose metaconglomerate, breccia, and basic igneous rocks. Includes schist locally.
Quaternary nonmarine deposits (Pleistocene)
Periglacial lacustrine deposits. Light-brown, well-sorted and bedded clayey sandstone and sandy clay with interbeds of volcanic ash and calcareous cemented gravels.
Silurian-Devonian rocks (Silurian-Devonian)
Mainly black argillite; some limestone, thin beds of conglomerate, sandstone, quartzite, and dolomite. Rocks confined to northwestern Pend Oreille County and adjacent Stevens County. Silurian age based on Monograptus and corals of several unusual genera; Devonian age based on coral fauna.
Tertiary marine and nonmarine rocks (Eocene)
Predominantly light-gray to olive-gray, fine to course-grained, thick-bedded sandstone with laminae to thick beds of medium dark gray siltstone, in northern Olympic Peninsula. Probably late Eocene to Miocene.
Tertiary nonmarine rocks, undivided (Tertiary; mostly Eocene)
Sandstone, shale, conglomerate, agglomerate, and tuff; includes some lava flows. Massive conglomerate, sandstone, siltstone, and ferruginous shale in northwestern Whatcom County.
Triassic sedimentary rocks, undivided (Triassic with Permian where impossible to differentiate)
Predominantly limestone, marble, and dolomite near Riverside in Okanogan County. Conglomerate, shale, graywacke, gritstone, and limestone on San Juan Island. Siltstone with greenstone locally on Orcas Island. Graywacke conglomerate, cherty greenstone, and limestone in northern Ferry County.
Upper Eocene volcanic rocks (Late Eocene)
Predominantly andesite flows and breccia; includes some basalt flows. Contains basaltic conglomerate, pyroclastic rocks, tuff beds, and sandstone in Chehalis-Centralia coal district, Lewis County.
Upper Eocene volcanic rocks (Late Eocene)
Andesite and basalt flows and associated breccia in central Lewis County. Pyroclastic rocks, mudflows, flow breccia, and volcanic-rich sedimentary rocks in King and Pierce Counties.
Upper Eocene volcanic rocks (Late Eocene to Oligocene)
Predominantly basalt flows and flow breccia; includes some pyroclastic and andesite rocks. Chiefly in western Washington.
Upper Jurassic-Lower Cretaceous sedimentary and volcanic rocks (Late Cretaceous-Jurassic)
Sedimentary and volcanic rocks, undivided. Graywacke, argillite, siltstone, slate, volcanic rocks, phyllite, greenschist, and greenstone.
Upper Jurassic-Lower Cretaceous sedimentary and volcanic rocks (Late Jurassic-Early Cretaceous)
Predominantly sedimentary rocks. Graywacke, argillite, and siltstone with some slate and phyllite; includes graywacke breccia and ribbon chert with minor local limestone lenses and basalt flows.
Upper Paleozoic rocks, undivided (Ordovician)
Mostly graywacke, interbedded quartzite and phyllite, greenstone and serpentine, and black shale with minor limestone. Some quartz-mica schist in Bald Knob area of Ferry County. Schist, gneiss, and amphibolite in other parts of Ferry County. Some rocks of lower Paleozoic age, possibly Precambrian, and Mesozoic may be included.
Upper Tertiary volcanic rocks, undivided (Miocene-Oligocene)
Mostly massive andesite flows, flow breccia, and pyroclastic material; includes some basalt flows and sedimentary rocks.
Upper Triassic and/or Lower Jurassic Marine Rocks (Cretaceous-Triassic)
Conglomerate, gritstone, graywacke, and carbonaceous argillite of northwestern Whatcom County.
Upper upper Eocene nonmarine and marine rocks (Middle Eocene)
Massive to thin-bedded, feldspathic to arkosic sandstone, siltstone, shale, and carbonaceous shale; becomes mostly marine in the western foothills of Cascade Mountains where coal beds are abundant. Basaltic sandstone and siltstone in northern Olympic Peninsula.
Wisconsin
Ancell Group (Ordovician)
Ancell Group - Orthoquartzitic sandstone with minor limestone, shale and conglomerate; includes Glenwood and St. Peter Formations
Copper Harbor Conglomerate (Middle Proterozoic)
Copper Harbor Conglomerate - Red lithic conglomerate and sandstone; mafic to felsic volcanic flows similar to those of the unnamed formation (unit Yu) are interlayered with the sedimentary rocks.
Jacobsville Sandstone (Middle Proterozoic)
Jacobsville Sandstone - Red, brown, and white quartzose sandstone, and minor siltstone, shale and conglomerate
Menominee Group; Blair Creek Formation (Early Proterozoic)
Menominee Group; Blair Creek Formation - Dominantly dark-gray, massive, porphyritic tholeiitic basalt. Includes a basal conglomerate and a lean iron-formation in middle of formation
Oronto Group; Freda Sandstone; Conglomerate member (Middle Proterozoic)
Oronto Group; Freda Sandstone; Conglomerate member
Quartzite (Early Proterozoic)
Quartzite - Maroon but locally white, gray, and red quartzite (quartz arenite) with a basal quartzose conglomerate. At Flambeau Ridge (Chippewa County) consists of conglomerate. Distinguished from other quartzite units in being strongly deformed and metamorphosed. Includes Flambeau, Rib Mountain, McCaslin, and Thunder Mountain Quartzites of local usage
Rhyolite at and near Cary Mound and near Brokaw (about 1835 Ma) (Early Proterozoic)
Rhyolite at and near Cary Mound and near Brokaw (about 1835 Ma) - Flow-banded rhyolite, welded tuff, volcanic conglomerate, and volcanogenic sedimentary rocks. Exposed in both Pembine-Wausau and Marshfield terranes.
Volcanic rocks, undivided (Early Proterozoic)
Volcanic rocks, undivided - Mafic to felsic flows, pyroclastic rocks, impure quartzite, and conglomerate in Eau Claire River, Eau Claire and northern Clark Counties. Rhyolite has zircon ages of 1,858 +/- 5 Ma. Possibly correlative with Milladore Volcanic Complex.
West Virginia
Chemung Group (Devonian)
Chemung Group - gray to brown siltstone and sandstone with shale and conglomeratic interbeds; mainly marine and sparingly fossiliferous; boundaries gradational. Can be divided into the Voreknobs and Scherr Formations along the Allegheny Front. Parkhead Sandstone Member near base.
Hampshire Formation (Devonian)
Hampshire Formation - non-marine shales and fine micaceous sandstones, mostly red to brownish-gray, including siltstone, sandstone and conglomerate. Generally distinguishable from the underlying Chemung by non-marine character and red color.
Stonehenge Limestone (Ordovician)
Stonehenge Limestone - gray, thin-bedded to massive, fossiliferous limestone, largely mechanically deposited, with small black chert nodules and beds of "edgewise" conglomerate. The highly resistant Stoufferstown Limestone member is found at the base.
Weverton-Loudoun Formation (Cambrian)
Weverton-Loudoun Formation (Chilhowee Group) - tough quartzitic sandstones, conglomerates, and shale.
Wyoming
Absaroka Volcanic Supergroup: Thoroughfare Creek Group--Aycross Formation (Phanerozoic | Cenozoic | Tertiary | Eocene (44-49 Ma))
ABSAROKA VOLCANIC SUPERGROUP: THOROFARE CREEK GROUP (AGE 44 TO 49 Ma) Aycross Formation (age 49 Ma)--Brightly variegated bentonitic claystone and tuffaceous sandstone, grading laterally into greenish-gray sandstone and claystone. In and east of Jackson Hole contains gold-bearing lenticular quartzite conglomerate.
Adaville Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
ADAVILLE FORMATION--Gray sandstone, siltstone, and carbonaceous claystone; conglomeratic in upper part; coal-bearing in lower part.
Bacon Ridge Sandstone (Phanerozoic | Mesozoic | Cretaceous-Late)
BACON RIDGE SANDSTONE--Gray to tan marine sandstone and thick coal beds; gold-bearing quartzite conglomerate in lower part.
Battle Spring Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)
BATTLE SPRING FORMATION--Equivalent to, and lithologically similar to locally derived basin-margin conglomerate of Wasatch Formation; merges southward into main body of Wasatch Formation. Lower part is Paleocene.
Bishop Conglomerate (Phanerozoic | Cenozoic | Tertiary | Oligocene )
BISHOP CONGLOMERATE--Clasts of red quartzite, gray chert, and limestone in a gray to white tuffaceous sandstone matrix.
Camp Davis Formation (Phanerozoic | Cenozoic | Tertiary | Miocene)
CAMP DAVIS FORMATION--Upper 5,000 ft chiefly red conglomerate and red claystone; underlain by white tuff, limestone, claystone, and basal gray conglomerate.
Chugwater and Goose Egg Formations (Phanerozoic | Paleozoic Mesozoic | Permian Triassic-Early(?) Triassic-Middle(?) Triassic-Late)
CHUGWATER AND GOOSE EGG FORMATIONS (north Wyoming). CHUGWATER FORMATION--Red siltstone and shale. Alcova Limestone Member in upper middle part in north Wyoming. Thin gypsum partings near base in north and northeast Wyoming. GOOSE EGG FORMATION--Red sandstone and siltstone, white gypsum, halite, and purple to white dolomite and limestone; CHUGWATER FORMATION OR GROUP (south Wyoming)--Red shale and siltstone containing thin gypsum partings near base. Group includes Popo Agie Formation (red shale and red, yellow, and purple siltstone; lenses of lime-pellet conglomerate), Crow Mountain Sandstone (red and gray, thick bedded), Alcova Limestone, and Red Peak Formation (red siltstone and shale). Chugwater Formation includes as members all the units listed above. Includes overlying Jelm Formation in Shirley and Seminoe Mountains and at northern end of Laramie Basin. JELM FORMATION--Red sandstone. GOOSE EGG FORMATION--Red sandstone and siltstone, white gypsum, halite, and purple to white dolomite and limestone.
Chugwater Formation (N, NE), or Chugwater Formation or Group (S) (Phanerozoic | Mesozoic | Triassic-Early Triassic-Middle(?) Triassic-Late)
CHUGWATER FORMATION (north, northeast Wyoming)--Red siltstone and shale. Alcova Limestone Member in upper middle part in north Wyoming. Thin gypsum partings near base in north and northeast Wyoming. [None mapped in the NE]; CHUGWATER FORMATION OR GROUP (south Wyomingt)--Red shale and siltstone containing thin gypsum partings near base. Group includes Popo Agie Formation (red shale and red, yellow, and purple siltstone; lenses of lime-pellet conglomerate), Crow Mountain Sandstone (red and gray, thick bedded), Alcova Limestone, and Red Peak Formation (red siltstone and shale). Chugwater Formation includes as members all the units listed above. Includes overlying Jelm Formation in Shirley and Seminoe Mountains and at northern end of Laramie Basin. JELM FORMATION--Red sandstone.
Cloverly and Morrison Formations (N,S) or Cloverly Formation, Inyan Kara Group, and Morrison Formation (Phanerozoic | Mesozoic | Jurassic-Late Cretaceous-Early)
CLOVERLY FORMATION and MORRISON FORMATION. CLOVERLY FORMATION--Rusty sandstone at top, underlain by brightly variegated bentonitic claystone; chert-pebble conglomerate locally at base. MORRISON FORMATION--Dully variegated claystone, nodular limestone, and gray silty sandstone. In southern Yellowstone and Jackson Hole areas the presence of Morrison is questionable; CLOVERLY FORMATION (Hartville uplift) or INYAN KARA GROUP (Black Hills) and MORRISON FORMATION. CLOVERLY FORMATION--Rusty to light-gray sandstone containing lenticular chert-pebble conglomerate interbedded with variegated bentonitic claystone. INYAN KARA GROUP--Rusty to light-gray sandstone containing lenticular chert-pebble conglomerate interbedded with variegated bentonitic claystone. Includes Fall River and Lakota Formations. MORRISON FORMATION, in northeast Wyoming, dully variegated siliceous claystone, nodular white limestone, and gray silty sandstone.
Cloverly, Morrison, and Sundance Formations (Phanerozoic | Mesozoic | Jurassic-Middle Jurassic-Late(?) Cretaceous-Early)
CLOVERLY, MORRISON, AND SUNDANCE (Js) FORMATIONS. CLOVERLY FORMATION--Rusty sandstone at top, underlain by brightly variegated bentonitic claystone; chert-pebble conglomerate locally at base. MORRISON FORMATION--Dully variegated claystone, nodular limestone, and gray silty sandstone. In southern Yellowstone and Jackson Hole areas the presence of Morrison is questionable. SUNDANCE FORMATION--Greenish-gray glauconitic sandstone and shale, underlain by red and gray nonglauconitic sandstone and shale.
Cloverly, Morrison, Sundance, and Gypsum Spring Formations (Phanerozoic | Mesozoic | Jurassic-Middle Jurassic-Late(?) Cretaceous-Early)
CLOVERLY, MORRISON, AND SUNDANCE (Js), AND GYPSUM SPRING FORMATIONS. CLOVERLY FORMATION--Rusty sandstone at top, underlain by brightly variegated bentonitic claystone; chert-pebble conglomerate locally at base. MORRISON FORMATION--Dully variegated claystone, nodular limestone, and gray silty sandstone. In southern Yellowstone and Jackson Hole areas the presence of Morrison is questionable. SUNDANCE FORMATION--Greenish-gray glauconitic sandstone and shale, underlain by red and gray nonglauconitic sandstone and shale. GYPSUM SPRING FORMATION--Interbedded red shale, dolomite, and gypsum. In north Wyoming wedges out south in T. 39 N.
Coalmont Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)
COALMONT FORMATION (EOCENE AND PALEOCENE)--Tan to gray arkosic micaceous soft sandstone, claystone, and locally derived conglomerate.
Conglomerate (Phanerozoic | Cenozoic | Tertiary Quaternary | Miocene Pliocene(?) Pleistocene)
CONGLOMERATE--Northwest Wyoming (Jackson Hole) (Pleistocene or Pliocene)--Paleozoic clasts, chiefly of Madison Limestone, in a lithified carbonate matrix; Central (Medicine Bow Mountains) and east Wyoming (east of Laramie Mountains) (Pleistocene to Miocene)--Giant granite boulders in an arkose matrix.
Conglomerate of Roaring Creek (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)
CONGLOMERATE OF ROARING CREEK (EOCENE OR PALEOCENE; OLDER THAN MAIN PART OF WASATCH FORMATION)--Red and gray conglomerate containing clasts of Mesozoic, Paleozoic, and Precambrian rocks.
Conglomerate of Sublette Range (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)
CONGLOMERATE OF SUBLETTE RANGE (EOCENE AND PALEOCENE)--Locally derived indurated angular conglomerate.
Crandall Conglomerate (Phanerozoic | Cenozoic | Tertiary | Eocene)
CRANDALL CONGLOMERATE--Nonvolcanic conglomerate containing clasts of Lower Paleozoic rocks.
Crooks Gap Conglomerate (Phanerozoic | Cenozoic | Tertiary | Eocene)
CROOKS GAP CONGLOMERATE--Giant boulders of granite in arkosic sandstone matrix. Reynolds (1976) considers age of eastern exposures to be Oligocene(?).
Ferris Formation (Phanerozoic | Mesozoic Cenozoic | Cretaceous-Late Tertiary | Paleocene)
FERRIS FORMATION--Brown and gray sandstone and shale; sparse carbonaceous shale and coal beds; thin lenses of pebble conglomerate.
Gannett Group (Phanerozoic | Mesozoic | Cretaceous-Early)
GANNETT GROUP--Red sandy mudstone, sandstone, and chert-pebble conglomerate; thin limestone and dark-gray shale in upper part, more conglomeratic in lower part. Includes Smoot Formation (red mudstone and siltstone), Draney Limestone, Bechler Conglomerate, Peterson Limestone, and Ephraim Conglomerate. Upper Jurassic fossils have been reported from the Ephraim.
Granitic conglomerate above or in upper part of Wasatch Formation (Phanerozoic | Cenozoic | Tertiary | Eocene)
GRANITIC CONGLOMERATE ABOVE OR IN UPPER PART OF WASATCH FORMATION--Giant granite boulders in arkosic sandstone matrix. Occurs along west margin of Wind River Range.
Green River and Wasatch Formations (Phanerozoic | Cenozoic | Tertiary | Eocene)
GREEN RIVER AND WASATCH FORMATIONS -- in Thrust Belt: GREEN RIVER FORMATION--Buff laminated marlstone and limestone, brown oil shale, and siltstone. Includes Angelo and Fossil Butte Members. WASATCH FORMATION--Variegated mudstone and sandstone. Includes Tunp and Bullpen Members, other tongues and unnamed members, and main body (variegated red to gray, brown, and gray mudstone and sandstone; conglomerate lenses); in southwest Wyoming -- GREEN RIVER FORMATION--Oil shale, light-colored tuffaceous marlstone, and sandstone. WASATCH FORMATION--Drab to variegated claystone and siltstone, carbonaceous shale and coal, buff sandstone, arkose, and conglomerate. In northwestern part of Green River Basin is thick arkosic light-yellowish-tan sandstone intertonguing with pale-green to gray claystone and shale.
Hanna Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene )
HANNA FORMATION--Brown and gray sandstone, shale, conglomerate, and coal; giant quartzite boulders near Medicine Bow Mountains.
Harebell Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
HAREBELL FORMATION--Gold-bearing quartzite conglomerate, olive-drab sandstone, and green claystone.
Heart Lake Conglomerate (Phanerozoic | Cenozoic | Tertiary | Pliocene)
HEART LAKE CONGLOMERATE--Abundant gray limestone and dolomite clasts and sparse rhyolite and quartzite clasts in a talc and clay matrix.
Hoback Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene )
HOBACK FORMATION--Interbedded drab and gray sandstone and claystone. Locally contains thick red and gray conglomerate.
Ice Point Conglomerate (Phanerozoic | Cenozoic | Tertiary | Eocene)
ICE POINT CONGLOMERATE--Reddish-brown conglomerate, chiefly of Paleozoic rock fragments.
Indian Meadows Formation (Phanerozoic | Cenozoic | Tertiary | Eocene)
INDIAN MEADOWS FORMATION--Red to variegated claystone, sandstone, and algal-ball(?) limestone; some beds of large Paleozoic boulders and detachment masses of Paleozoic and Mesozoic rocks.
Kootenai and Morrison Formations and Ellis Group (Phanerozoic | Mesozoic | Jurassic-Middle Jurassic-Late(?) Cretaceous-Early)
KOOTENAI AND MORRISON FORMATIONS AND ELLIS GROUP. KOOTENAI FORMATION--Rusty thin-bedded sandstone, grayish-red soft claystone, white limestone, and chert-pebble conglomerate. MORRISON FORMATION in northern Yellowstone area--Variegated silty claystone and fine-grained sandstone. ELLIS GROUP includes SWIFT, RIERDON, and SAWTOOTH FORMATIONS. Swift Formation--Calcareous glauconitic sandstone and sandy limestone. Rierdon Formation--Mudstone, siltstone, shale, and basal limestone. Sawtooth Formation--Red beds and limestone.
Lance Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
LANCE FORMATION north Wyoming--Thick-bedded buff sandstone and drab to green shale; thin conglomerate lenses; south and northeast Wyoming--Brown and gray sandstone and shale; thin coal and carbonaceous shale beds.
Landslide Creek Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
LANDSLIDE CREEK FORMATION--Greenish-gray bentonitic tuffaceous sandstone and conglomerate.
Mesaverde Formation (N) or Mesaverde Group (S) (Phanerozoic | Mesozoic | Cretaceous-Late)
MESAVERDE FORMATION (north Wyoming)--Light-colored massive to thin-bedded sandstone, gray sandy shale, and coal beds. In Jackson Hole locally contains gold-bearing quartzite conglomerate. North of North Fork Powder River east of the Bighorn Mountains, consists solely of the Parkman Sandstone Member; MESAVERDE GROUP (SOUTH WYOMING). Includes Almond Formation, Ericson Sandstone, Rock Springs and Blair Formations in Rock Springs uplift; Almond Formation (white and brown soft sandstone, gray sandy shale, coal and carbonaceous shale), Pine Ridge Sandstone (light-gray sandstone and thin coal beds), and Allen Ridge (gray sandstone, shale, and thin coal beds) and Haystack Mountains (gray marine sandstone and shale) Formations in Rawlins uplift; Pine Ridge Sandstone (light-gray sandstone and thin coal beds) and Rock River Formation (soft sandstone and sandy shale) in Laramie Basin.
Mesaverde Group, Ericson Sandstone (Phanerozoic | Mesozoic | Cretaceous-Late)
MESAVERDE GROUP (SOUTH WYOMING). Rock Springs uplift. Ericson Sandstone--White massive sandstone; lenticular chert-grit conglomerate in upper part.
Miocene Rocks (Phanerozoic | Cenozoic | Tertiary | Miocene)
MIOCENE ROCKS--Southwest Wyoming: Southern Rock Springs uplift--Pale-green to tan tuffaceous sandstone and claystone of Miocene(?) age. Conglomerate of uncertain correlation locally at base. Saratoga Valley and west and southwest to Colorado--White massive soft tuffaceous sandstone and lesser amounts of white marl; lower part conglomeratic. Underlies North Park Formation in Saratoga Valley. To the west and southwest is called Browns Park Formation. Rawlins area--White massive soft tuffaceous sandstone; Central Wyoming: White soft tuffaceous sandstone. Locally derived conglomerate in upper and lower parts of sequence; in places lower conglomeratic sequence may be of Oligocene age. In Granite Mountains K/Ar age of tuff in lower part of sandstone sequence about 17 Ma and fission-track age of lower conglomerate about 24 Ma.
Pass Peak Formation and Equivalents (Phanerozoic | Cenozoic | Tertiary | Eocene)
PASS PEAK FORMATION AND EQUIVALENTS--Includes Lookout Mountain Conglomerate Member of Wasatch Formation. On the south side of Gros Ventre Range consists of gold-bearing quartzite conglomerate; intertongues southward with sandstone and claystone of main body of Wasatch Formation.
Phosphoria, Wells, and Amsden Formations (TB), Phosphoria Formation and related rocks, Quadrant Sandstone, and Amsden Formation (Y), or Phosphoria Formation and related rocks, Tensleep Sandstone, and Amsden Formation (N) (Phanerozoic | Paleozoic | Carboniferous Mississippian-Late Pennsylvanian(?) Permian)
PHOSPHORIA, WELLS, AND AMSDEN FORMATIONS (Thrust Belt). PHOSPHORIA FORMATION--Upper part is dark- to light-gray chert and shale with black shale and phosphorite at top; lower part is black shale, phosphorite, and cherty dolomite. WELLS FORMATION--Gray limestone interbedded with yellow limy sandstone. AMSDEN FORMATION--Red and gray cherty limestone and shale, sandstone, and conglomerate. PHOSPHORIA FORMATION AND RELATED ROCKS, QUADRANT SANDSTONE, AND AMSDEN FORMATION (Yellowstone). PHOSPHORIA FORMATION AND RELATED ROCKS--Brown sandstone and dolomite, cherty phosphatic and glauconitic dolomite, phosphatic sandstone and dolomite, and greenish-gray to black shale. Intertonguing equivalent is Shedhorn Sandstone. QUADRANT SANDSTONE--Light-gray sandstone. AMSDEN FORMATION--Red and green dolomitic shale, siltstone, and sandstone. PHOSPHORIA FORMATION AND RELATED ROCKS, TENSLEEP SANDSTONE, AND AMSDEN FORMATION (north Wyoming). PHOSPHORIA FORMATION AND RELATED ROCKS--Brown sandstone and dolomite, cherty phosphatic and glauconitic dolomite, phosphatic sandstone and dolomite, and greenish-gray to black shale. Intertonguing equivalents of parts of Phosphoria are Park City Formation (primarlily cherty dolomite, limestone, and phosphatic gray shale) and Shedhorn Sandstone. TENSLEEP SANDSTONE--White to gray sandstone containing thin limestone and dolomite beds. Permian fossils have been found in the topmost beds of the Tensleep at some localities in Washakie Range, Owl Creek Mountains, and southern Bighorn Mountains. AMSDEN FORMATION--Red and green shale and dolomite; at base is brown sandstone.
Pinyon Conglomerate (Phanerozoic | Mesozoic Cenozoic | Cretaceous-Late Tertiary | Paleocene)
PINYON CONGLOMERATE--Brown gold-bearing quartzite conglomerate interbedded with brown and gray sandstone. Age of basal part about 67 Ma in northeastern Jackson Hole; farther south entire sequence is Paleocene.
Red Conglomerate on top of Hoback and Wyoming Ranges (Phanerozoic | Cenozoic | Tertiary | Miocene)
RED CONGLOMERATE ON TOP OF HOBACK AND WYOMING RANGES (MIOCENE?; MAY BE AS OLD AS EOCENE)--Locally derived clasts of Mesozoic and Paleozoic rocks in a red clay and sand matrix.
Sandstone and Conglomerate (Phanerozoic | Cenozoic | Tertiary | Oligocene Miocene)
SANDSTONE AND CONGLOMERATE--Gray hard coarse-grained sandstone and conglomerate.
Sohare Formation and Bacon Ridge Sandstone (Phanerozoic | Mesozoic | Cretaceous-Late)
SOHARE FORMATION AND BACON RIDGE SANDSTONE. SOHARE FORMATION (Kso)--Lenticular gray and brown sandstone and shale; thin coal beds. BACON RIDGE SANDSTONE (Kb)--Gray to tan marine sandstone and thick coal beds; gold-bearing quartzite conglomerate in lower part.
Teewinot Formation (Phanerozoic | Cenozoic | Tertiary | Miocene)
TEEWINOT FORMATION (AGE ABOUT 9 Ma)--White lacustrine clay, tuff, and limestone. In thrust belt includes conglomerate.
Upper Miocene Rocks (Phanerozoic | Cenozoic | Tertiary | Miocene-Late)
UPPER MIOCENE ROCKS--Southwest Wyoming: South end of Wind River Range--Siliceous, arkosic, and locally radioactive sandstone, claystone, and conglomerate. Fission-track age about 27 Ma. Recent work suggests that part of these deposits may be of Eocene age. Pliocene and Miocene (as originally defined 2) South Pass Formation. Saratoga Valley--White to greenish-gray tuffaceous sandstone, siltstone, and claystone; locally conglomeratic. North Park Formation; Central Wyoming: Arkosic sandstone, conglomerate, and siltstone; some light-colored tuffaceous radioactive claystone and white cherty limestone. North of Sweetwater River in Granite Mountains--Light-colored tuffaceous radioactive claystone, siltstone, sandstone, and arkose. Moonstone Formation; East Wyoming: Light-colored tuffaceous claystone, sandstone, and conglomerate. Ogallala Formation in Denver Basin.
Volcanic Conglomerate (Phanerozoic | Cenozoic | Tertiary | Eocene)
VOLCANIC CONGLOMERATE--Dark-brown to black conglomerate, poorly bedded, composed chiefly of basalt clasts in a basaltic tuff matrix.
Wagon Bed Formation (Phanerozoic | Cenozoic | Tertiary | Eocene (45-49 Ma))
WAGON BED FORMATION (AGE ABOUT 45 TO 49 Ma)--Southwest and central Wyoming--Green and gray tuffaceous claystone, sandstone, and conglomerate; some uranium-phosphate marlstone and variegated bentonitic claystone. Locally contains oil shale between Wind River and Bighorn Basins; Central Wyoming (west side of Laramie Mountains)--Dull-green siliceous bentonitic claystone and tuff; giant granite boulder conglomerate in tuffaceous matrix.
Wasatch Formation (Phanerozoic | Cenozoic | Tertiary | Eocene)
WASATCH FORMATION -- in Thrust belt: Main body--Variegated red to gray, brown, and gray mudstone and sandstone; conglomeratic lenses; in southwest Wyoming--Drab to variegated claystone and siltstone, carbonaceous shale and coal, buff sandstone, arkose, and conglomerate. In northwestern part of Green River Basin is thick arkosic light-yellowish-tan sandstone intertonguing with pale-green to gray claystone and shale; in east Wyoming--Drab sandstone and drab to variegated claystone; numerous coal beds in lower part.
Wasatch Formation (E) (Phanerozoic | Cenozoic | Tertiary | Eocene)
WASATCH FORMATION Moncrief Member--Conglomerate of Precambrian clasts, interbedded with drab sandstone and claystone.
Wasatch Formation (E) (Phanerozoic | Cenozoic | Tertiary | Eocene)
WASATCH FORMATION Kingsbury Conglomerate Member--Conglomerate of Paleozoic clasts, interbedded with drab sandstone and variegated claystone.
Wasatch Formation (SW) (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)
WASATCH FORMATION Main body--Drab sandstone, drab to variegated claystone and siltstone; locally derived conglomerate around basin margins. Lower part is Paleocene.
Wasatch Formation (SW) (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)
WASATCH FORMATION La Barge and Chappo Members--Red, gray, and brown mudstone and conglomerate and yellow sandstone. La Barge Member tongues out to north at about T. 35 N. Lower part of Chappo is Paleocene.
Wells and Amsden Formations (TB), or Casper Formation and Madison Limestone (N, S) (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early Pennsylvanian-Middle(?) Pennsylvanian-Late(?) Permian)
WELLS AND AMSDEN FORMATIONS (Thrust Belt). WELLS FORMATION--Gray limestone interbedded with yellow limy sandstone. AMSDEN FORMATION--Red and gray cherty limestone and shale, sandstone, and conglomerate. CASPER FORMATION AND MADISON LIMESTONE (north, south Wyoming). CASPER FORMATION--Gray, tan, and red thick-bedded sandstone underlain by interbedded sandstone and pink and gray limestone. May include some Devonian(?) sandstone along east flank of Laramie Mountains. MADISON LIMESTONE--Includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite).
White River Formation--Upper conglomerate member (Phanerozoic | Cenozoic | Tertiary | Oligocene )
WHITE RIVER FORMATION Upper conglomerate member--Light-gray soft conglomeratic tuffaceous sandstone and conglomerate of Precambrian clasts.
Willwood Formation (Phanerozoic | Cenozoic | Tertiary | Eocene)
WILLWOOD FORMATION--Variegated claystone, shale, and sandstone; some lenticular gold-bearing quartzite conglomerate.
Wind River Formation and Indian Meadows Formations (Phanerozoic | Cenozoic | Tertiary | Eocene)
WIND RIVER AND INDIAN MEADOWS FORMATIONS. WIND RIVER FORMATION Central Wyoming (Twdr2)--Variegated claystone and sandstone; lenticular conglomerate. Age of tuff at top 49 Ma. INDIAN MEADOWS FORMATION (Twim)--Red to variegated claystone, sandstone, and algal-ball(?) limestone; some beds of large Paleozoic boulders and detachment masses of Paleozoic and Mesozoic rocks.

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