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Geologic units containing Mudstone

Mudstone
A general term that includes claystone, siltstone, shale, and argillite, and that should be used only when the amounts of clay-sized and silt-sized particles are not known or specified, or cannot be precisely identified...
Subtopics:
Argillite
Claystone
Shale
Siltstone

Alabama - Arkansas - Arizona - California - Colorado - Florida - Iowa - Indiana - Kansas - Louisiana - Massachusetts - Maryland - Maine - Michigan - Minnesota - Montana - North Carolina - Nebraska - New Jersey - New Mexico - Nevada - New York - Ohio - Oklahoma - Oregon - Pennsylvania - South Carolina - South Dakota - Tennessee - Texas - Utah - Virginia - Washington - Wisconsin - West Virginia - Wyoming

Alabama

Athens Shale and Lenoir Limestone undifferentiated (Ordovician)
Athens Shale and Lenoir Limestone undifferentiated - Athens Shale -- black graptolitic shale, locally contains interbedded dark-gray limestone. Lenoir Limestone -- dark-gray medium to thick-bedded argillaceous limestone; locally contains an interval of fenestral mudstone at the base (Mosheim Limestone Member).
Bangor and Monteagle Limestones undivided in part (Mississippian)
Bangor and Monteagle Limestones undivided in part - Bangor Limestone -- medium-gray bioclastic and oolitic limestone, containing interbeds of dusky-red and olive-green mudstone in upper part. Monteagle Limestone -- light-gray oolitic limestone containing interbedded argillaceous, bioclastic, or dolomitic limestone, dolomite, and medium-gray shale.
Bangor Limestone (Mississippian)
Bangor Limestone - Medium-gray bioclastic and oolitic limestone, containing interbeds of dusky-red and olive-green mudstone in upper part.
Bangor Limestone (Mississippian)
Bangor Limestone - Medium-gray bioclastic and oolitic limestone, containing interbeds of dusky-red and olive-green mudstone in the upper part.
Bangor Limestone (Mississippian)
Bangor Limestone - Medium-gray bioclastic and oolitic limestone, containing interbeds of dusky-red and olive-green mudstone in upper part.
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.
Frog Mountain Sandstone (Devonian)
Frog Mountain Sandstone -- light to dark-gray sandstone with thin dark-gray shale interbeds, light-gray to black dolomudstone, glauconitic limestone, and fossiliferous chert locally in lower part.
Greensport Formation (Ordovician)
Greensport Formation - variegated dusky-red and dark-yellowish-orange shale, calcareous mudstone, limestone, siltstone, and minor sandstone.
Little Oak and Lenoir Limestones undifferentiated (Ordovician)
Little Oak and Lenoir Limestones undifferentiated - dark-gray argillaceous, fossiliferous medium to thick-bedded limestone; locally contains rare chert in upper part and an interval of fenestral mudstone in lower part (Mosheim Limestone Member of the Lenoir Limestone). Between Siluria and Pelham in Shelby County, the Little Oak and Lenoir Limestones are separated by a tongue of the Athens Shale.
Nichols Formation (Cambrian)
Nichols Formation - massive to laminated greenish-gray and black micaceous mudstone containing minor interbeds of siltstone and very fine-grained sandstone.
Paleozoic shale undifferentiated (Mississippian)
Paleozoic shale undifferentiated - Dark-gray shale and mudstone, locally containing thin interbeds and lenses of dark-greenish-gray sandstone includes probable Floyd Shale in area east of Gadsden, Etowah County.
Paleozoic shale undifferentiated (Mississippian)
Paleozoic shale undifferentiated - Dark-gray shale and mudstone, locally containing thin interbeds and lenses of dark-greenish-gray sandstone includes Athens Shale and probable Floyd Shale in the structural windows near Anniston, Calhoun County.
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.
Parkwood Formation (Pennsylvanian-Mississippian)
Parkwood Formation - Interbedded medium to dark-gray shale and light to medium-gray sandstone; locally contains dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal.
Parkwood Formation (Pennsylvanian-Mississippian)
Parkwood Formation - Interbedded medium to dark-gray shale and light to medium-gray sandstone; locally contains dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal.
Parkwood Formation and Floyd Shale undifferentiated (Pennsylvanian-Mississippian)
Parkwood Formation and Floyd Shale undifferentiated - Parkwood Formation -- Interbedded medium to dark-gray shale and light to medium-gray sandstone; locally contains dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal. Floyd Shale -- Dark-gray shale, sideritic in part; thin beds of sandstone, limestone and chert are locally present; beds of partly bioclastic, partly argillaceous limestone are abundant in parts of Calhoun and Cherokee Counties.
Pennington Formation (Mississippian)
Pennington Formation - Medium-gray shale, containing interbedded limestone, dolomite, argillaceous sandstone, dusky-red and grayish-olive mudstone, and minor shaly coal. Mainly restricted to eastern part of Interior Low Plateaus province and where less than 100 feet thick the formation is included in the Bangor Limestone.
Pennington Formation (Mississippian)
Pennington Formation - Medium-gray shale, containing interbedded limestone, dolomite, argillaceous sandstone, dusky-red and grayish-olive mudstone, and minor shaly coal. Mainly restricted to northeastern AL and part of the Sequatchie anticline. Where less than 100 feet thick the formation is included in the Bangor Limestone.
Pride Mountain Formation (Mississippian)
Pride Mountain Formation - Medium to dark-gray shale, containing one to three units of a variable combination of sandstone and limestone in the lower part; locally contains rare interbeds of dusky-red and greenish-gray mudstone.
Pride Mountain Formation (Mississippian)
Pride Mountain Formation - Medium to dark-gray shale, containing one to three units of a variable combination of sandstone and limestone in the lower part; locally contains rare interbeds of dusky-red and greenish-gray mudstone.
Pride Mountain Formation (Mississippian)
Pride Mountain Formation - Medium to dark-gray shale, containing one to three units of a variable combination of sandstone and limestone in the lower part; locally contains rare interbeds of dusky-red and greenish-gray mudstone.
Rome Formation (Cambrian)
Rome Formation - variegated thinly interbedded mudstone, shale, siltstone, and sandstone; limestone and dolomite occur locally. Quartzose sandstone commonly present near top of formation.
Sequatchie Formation (Ordovician)
Sequatchie Formation - Grayish-red, grayish-green, and yellowish-gray thin-bedded calcareous shale and calcareous mudstone containing interbedded fossiliferous limestone, and medium-gray to moderate-red partly sandy and glauconitic, medium to coarse-grained bioclastic limestone. In Jackson County, includes the Leipers Limestone and Inman Formation.
Sequatchie Formation (Ordovician)
Sequatchie Formation - Grayish-red, grayish-green, and yellowish-gray thin-bedded calcareous shale and calcareous mudstone containing interbedded fossiliferous limestone, and medium-gray to moderate-red partly sandy and glauconitic, medium to coarse-grained bioclastic limestone.
Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated (Ordovician)
Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated - variegated dusky-red and pale-yellowish-orange shale, calcareous mudstone, dolomite, siltstone, and minor sandstone. Mapped in areas of facies transition with the Chickamauga Limestone (Scraper Mountain) and in the structurally complex area at the east end of Dry Creek Mountain.
Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated (Ordovician)
Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated - variegated dusky-red and pale-yellowish-orange shale, calcareous mudstone, dolomite, siltstone, and minor sandstone. Mapped in areas of facies transition with the Chickamauga Limestone (Canoe Creek, Dunaway, and Hensley Mountains).
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

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)
Glen Canyon Group (Early Jurassic)
Conspicuous red, cross-bedded Wingate Sandstone and the conspicuously cross-bedded, eolian, red to buff Navajo Sandstone form prominent cliffs in northern Arizona. These two sandstone units are separated by variably colored siltstone, silty sandstone, and sandstone of the Kayenta and Moenave Formations. (180-210 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)
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 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 sedimentary rocks (Permian)
Gray to tan, cherty limestone of Kaibab and Toroweap Formations, and underlying white to tan, fine-grained Coconino Sandstone. Limestone was deposited in a shallow sea, and sandstone was deposited in near-shore dunes and beach settings. (270-280 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 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)
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)

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 2 (SE California Carbonate Assemblage) (Mississippian 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
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 (West Walker River) (Triassic(?) and/or Jurassic(?))
Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges
Cretaceous marine rocks (in part nonmarine), unit 3 (Mescal Range) (Middle Jurassic to late Early Cretaceous)
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.
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 2 (Coast Ranges) (Late Jurassic to Early Cretaceous)
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
Lower Cretaceous marine rocks (Early Cretaceous)
Lower Cretaceous sandstone, shale, and conglomerate
Lower Cretaceous marine rocks (?) (Cretaceous (?))
Lower Cretaceous sandstone, shale, and conglomerate (?)
Miocene marine rocks (Oligocene to Pliocene)
Sandstone, shale, siltstone, conglomerate and breccia; in part Pliocene and Oligocene.
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 marine rocks (Eocene to Miocene)
Sandstone, shale, and conglomerate; in part Miocene and Eocene.
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.
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
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 8 (Northeastern Klamath Mountains) (Ordovician(?) to Devonian(?))
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
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 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.
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.
Silurian and/or Ordovician marine rocks, unit 1 (Death Valley) (Ordovician to Early Devonian)
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 4 (West Walker River) (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, 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

Bridger Fm (Phanerozoic | Cenozoic | Tertiary)
Claystone and mudstone; in Sand Wash basin
Chinle and Chugwater Fms (Phanerozoic | Mesozoic | Triassic)
Chugwater Fm (Phanerozoic | Mesozoic | Triassic)
Red sandstone, siltstone, shale, and local limestone and gypsum
Dakota and Morrison Fms (Phanerozoic | Mesozoic | Jurassic Cretaceous)
Dakota, Burro Canyon, Morrison, and Junction Creek Fms (Phanerozoic | Mesozoic | Jurassic Cretaceous)
Burro Canyon is locally absent
Dakota, Burro Canyon, Morrison, and Wanakah Fms (Phanerozoic | Mesozoic | Jurassic Cretaceous)
Dakota Group and Morrison And Ralston Creek Fms at mountain front between Boulder and Colorado Springs. Dakota, Purgatoire, Morrison, and Ralston Creek Fms in Canon City area (Phanerozoic | Mesozoic | Jurassic Cretaceous)
Dakota, Morrison, and Sundance Fms (Phanerozoic | Mesozoic | Jurassic Cretaceous)
Dakota, Purgatoire, Morrison, Ralston Creek, and Entrada Fms in southeast. Dakota, Morrison, and Entrada Fms in central mountains. Dakota, Burro Canyon, Morrison, Wanakah, and Entrada Fms in Gunnison River area. Dakota, Morriso (Phanerozoic | Mesozoic | Jurassic 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
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)
Green River Fm (Phanerozoic | Cenozoic | Tertiary)
Marlstone, sandstone, and oil shale
Green River Fm--Lower Part (Phanerozoic | Cenozoic | Tertiary)
Shale, sandstone, marlstone, and limestone in Anvil Points, Garden Gulch, and Douglas Creek Members; in Piceance basin
Green River Fm--Luman Tongue (Phanerozoic | Cenozoic | Tertiary)
Carbonaceous shale and marlstone; in Sand Wash basin
Green River Fm--Parachute Creek Member (Phanerozoic | Cenozoic | Tertiary)
Parachute Creek Member--Oil shale, marlstone, and siltstone; in Piceance basin
Jelm, Lykins, Lyons, and Satanka Fms (Phanerozoic | Paleozoic Mesozoic | Permian Triassic)
Red siltstone, shale, and sandstone
Laramie Fm and Fox Hills Sandstone (Phanerozoic | Mesozoic | Cretaceous)
Lykins Fm and Lyons Sandstone (Phanerozoic | Paleozoic Mesozoic | Permian Triassic)
Moenkopi Fm (Phanerozoic | Mesozoic | Triassic)
Red siltstone, mudstone, sandstone, and local gypsum
Morrison and Ralston Creek Fms (Phanerozoic | Mesozoic | Jurassic)
Ralston Creek Fm: Claystone, sandstone, limestone, and gypsum
Morrison, Curtis, and Entrada Fms (Phanerozoic | Mesozoic | Jurassic)
In extreme southwestern Moffat County, includes thin wedge of Carmel Fm (red siltstone and sandstone) beneath Entrada
Morrison, Curtis, Entrada, and Glen Canyon Fms (Phanerozoic | Mesozoic | Triassic Jurassic)
Curtis is absent along Grand Hogback
Morrison, Entrada, and Chinle Fms (Phanerozoic | Mesozoic | Triassic Jurassic)
Along southern Grand Hogback, Chinle is represented only by basal Gartra Sandstone Member
Morrison Fm (Phanerozoic | Mesozoic | Jurassic)
Variegated claystone, mudstone, sandstone, and local beds of limestone
Morrison Fm and Curtis Fm (Phanerozoic | Mesozoic | Jurassic)
Morrison Fm: Variegated claystone, mudstone, sandstone, and local beds of limestone. Curtis Fm: glauconitic sandstone and limestone
Morrison Fm and Entrada Sandstone (Phanerozoic | Mesozoic | Jurassic)
Morrison Fm and Junction Creek Sandstone (Phanerozoic | Mesozoic | Jurassic)
In Gunnison River area east of wedgeout of all units of Wanakah Fm (Jmw) except the Junction Creek Member
Morrison Fm and Sundance Fm (Phanerozoic | Mesozoic | Jurassic)
Sundance Fm: Sandstone, shale, claystone, and limestone
Morrison Fm and Wanakah Fm (Junction Creek Sandstone Member at or near top; Pony Express Limestone Member at base) (Phanerozoic | Mesozoic | Jurassic)
Wanakah Fm: Sandstone, shale, limestone, and local gypsum
Morrison Fm, Summerville Fm, and Entrada Sandstone (Phanerozoic | Mesozoic | Jurassic)
Summerville Fm: Shale and siltstone
Morrison, Ralston Creek, and Entrada (or Exeter) Fms (Phanerozoic | Mesozoic | Jurassic)
Morrison, Wanakah, and Entrada Fms (Phanerozoic | Mesozoic | Jurassic)
Raton Fm (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Arkosic sandstone, siltstone, and shale; contains major coal deposits in Raton Basin
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
Wasatch Fm--Cathedral Bluffs Tongue (Phanerozoic | Cenozoic | Tertiary)
Claystone, mudstone, and sandstone; in Sand Wash basin
Wasatch Fm (including Fort Union equivalent at base) and Ohio Creek Fm (Phanerozoic | Cenozoic | Tertiary)
Claystone, mudstone, sandstone, and conglomerate
Wasatch Fm--Niland Tongue (Phanerozoic | Cenozoic | Tertiary)
Mudstone, sandstone, and carbonaceous shale; in Sand Wash basin

Florida

Avon Park Formation (Eocene)
Avon Park Formation - Middle Eocene carbonate sediments of peninsular Florida, as originally described by Applin and Applin (1944), were subdivided, in ascending order, into the Lake City Limestone and the Avon Park Limestone. Miller (1986) recommended combining the Lake City Limestone with the Avon Park Limestone and, due to the common occurrence of dolostone, referred to the unit as the Avon Park Formation. Carbonates of the Avon Park Formation are the oldest sediments exposed in the state. The Avon Park Formation crops out in a limited area in west-central peninsular Florida in Levy and Citrus Counties on the crest of the Ocala Platform. The Avon Park Formation consists of cream to light-brown or tan, poorly indurated to well indurated, variably fossiliferous, limestone (grainstone, packstone and wackestone, with rare mudstone). These limestones are interbedded with tan to brown, very poorly indurated to well indurated, very fine to medium crystalline, fossiliferous (molds and casts), vuggy dolostones. The fossils present include mollusks, foraminifers, echinoids, algae and carbonized plant remains. Molds and casts of gypsum crystals occur locally. The Avon Park Formation is part of the Floridan aquifer system (FAS). Parts of the Avon Park Formation comprise important, subregional confining units within the FAS (Miller, 1986).
Hawthorn Group, Arcadia Formation, Tampa Member (Oligocene/Miocene)
Hawthorn Group, Arcadia Formation, Tampa Member - The Tampa Member consists predominantly of limestone with subordinate dolostone, sand and clay (Scott, 1988). The lithology of the Tampa Member is very similar to that of the subsurface limestone part of the Arcadia Formation except that the Tampa Member contains noticeably less phosphate (Scott, 1988). The limestone in the Tampa is white to yellowish gray, fossiliferous and variably sandy and clayey mudstone, wackestone and packstone with minor to no phosphate grains. Sand and clay beds are like those in the undifferentiated Arcadia Formation. Mollusks and corals are common in the Tampa Member as molds and casts, silicified pseudomorphs and original shell material. The Tampa Member and the lower part of the Arcadia Formation form the upper part of the Floridan aquifer system (FAS) in parts of southern Florida (Miller, 1986; Scott, 1991).
Hawthorn Group, Peace River Formation (Miocene/Pliocene)
Hawthorne Group, Peace River Formation - The Peace River Formation crops out or is beneath a thin overburden on the southern part of the Ocala Platform extending into the Okeechobee Basin. These sediments were mapped from Hillsborough County southward to Charlotte County. Within this area, the Peace River Formation is composed of interbedded sands, clays and carbonates. The sands are generally light gray to olive gray, poorly consolidated, clayey, variably dolomitic, very fine to medium grained and phosphatic. The clays are yellowish gray to olive gray, poorly to moderately consolidated, sandy, silty, phosphatic and dolomitic. The carbonates are usually dolostone in the outcrop area. The dolostones are light gray to yellowish gray, poorly to well indurated, variably sandy and clayey, and phosphatic. Opaline chert is often found in these sediments. The phosphate content of the Peace River Formation sands is frequently high enough to be economically mined. Fossil mollusks occur as reworked casts, molds, and limited original shell material. Silicified corals and wood, and vertebrate fossils are also present. The Peace River Formation is widespread in southern Florida. It is part of the intermediate confining unit/aquifer system.
Suwannee Limestone- Marianna Limestone undifferentiated (Oligocene)
Suwannee Limestone- Marianna Limestone undifferentiated - Undifferentiated Lower Oligocene Sediments - The undifferentiated Lower Oligocene sediments of the central panhandle consist of white to cream-colored, poorly to well indurated, variably fossiliferous limestones (grainstone, packstone, wackestone and mudstone). Glauconite occurs in some sediments. Siliciclastics form a minor component in some sediments. Thin beds of siliciclastics (Byram Marl and Buccatuna Formation) are included in the undifferentiated Lower Oligocene sediments. The Lower Oligocene carbonates form important parts of the upper FAS (Miller, 1986).

Iowa

Indiana

Kansas

Louisiana

Massachusetts

East Berlin Formation (Lower Jurassic)
East Berlin Formation - Reddish-brown to pale red arkosic sandstone and siltstone, and gray sandstone, gray mudstone, and black shale; interpreted as lake beds. Assigned to Newark Supergroup (Robinson and Luttrell, 1985). 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).
Newbury Volcanic Complex (Lower Devonian and Upper Silurian)
Newbury Volcanic Complex - Upper members. Calcareous mudstone, red mudstone, and siliceous siltstone; fossils of Late Silurian through Early Devonian age.
Newbury Volcanic Complex (Lower Devonian and Upper Silurian)
Newbury Volcanic Complex - Porphyritic andesite, includes tuffaceous mudstone beds containing fossils of Late Silurian through Early Devonian age.
New Haven Arkose (Upper Triassic)
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; TRn is continuous with and lithically similar to TRs near Northampton. Assigned to Newark Supergroup (Robinson and Luttrell, 1985).
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).
Shuttle Meadow Formation (Lower Jurassic)
Shuttle Meadow Formation - Reddish-brown to pale red arkosic sandstone and siltstone, and gray sandstone, gray mudstone, and black shale; interpreted as lake beds. 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 (Upper Triassic)
Sugarloaf Formation - Red, pink, and gray coarse-grained, locally conglomeratic arkose, interbedded with brick-red shaley siltstone and fine-grained arkosic sandstone; boundary between Lower Jurassic (Js, Jsc) and Upper Triassic (TRs) parts are arbitrarily drawn through rocks of similar lithology on basis of Lower Jurassic palynofloral zone in gray mudstone immediately below Deerfield (Jdb); TRs is continuous with and lithically similar to TRn near Northampton. Assigned to Newark Supergroup and revised to include all sedimentary strata in the Deerfield basin below the Deerfield Basalt or its projected horizon. The Late Triassic-Early Jurassic boundary is arbitrarily drawn through clastic rocks consisting of coarse-grained, locally conglomeratic arkose interbedded with sandstone and siltstone below a Lower Jurassic palynofloral zone in gray mudstone just below the base of the Deerfield Basalt. The Sugarloaf is continuous with and lithologically similar to the New Haven Arkose in the Hartford basin (Robinson and Luttrell, 1985).

Maryland

Hampshire Formation (Devonian)
Hampshire Formation - Interbedded red shale, red mudstone, and red to brown cross-bedded siltstone and sandstone; some thin green shale; greenish-gray sandstone and shale toward top; fragmentary plant fossils; thickness 1,400 to 2,000 feet in west, increases to 3,800 feet in east.
Mauch Chunk Formation (Mississippian)
Mauch Chunk Formation - Red and green shale, reddish-purple mudstone, and red, green, brown, and gray thin-bedded and cross-bedded sandstones; thickness 500 feet in west, increases to about 800 feet in east.
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.
Wills Creek Shale and Bloomsburg Formation (Silurian)
Wills Creek Shale - Olive to yellowish-gray, thin-bedded mudstone, calcareous shale, argillaceous limestone, and sandstone; thickness 450 feet in west, increases to 600 feet in east; and Bloomsburg Formation - Bright red, hematitic, thin- to thick-bedded sandstone and shale; some dark sandstone and green shale; Cedar Creek Limestone Member - Dark gray, fine- to medium-grained argillaceous limestone, occurs in middle part of formation; total thickness 20 feet in west, increases to 200 feet in east.

Maine

Cambrian Caucomgomoc Lake Formation, quartzwacke and pelite member (Cambrian)
Cambrian Caucomgomoc Lake Formation quartzwacke and pelite member
Cambrian Grand Pitch Formation (Cambrian)
Cambrian Grand Pitch Formation
Cambrian Jim Pond Formation, quartzwacke and pelite (Cambrian)
Cambrian Jim Pond Formation, quartzwacke and pelite
Cambrian Jim Pond Formation siltstone, mudstone, and pelite (Cambrian)
Cambrian Jim Pond Formation siltstone, mudstone, and pelite
Cambrian Loon Stream Formation (Cambrian)
Cambrian Loon Stream Formation
Devonian Beck Pond Limestone (Devonian)
Devonian Beck Pond Limestone
Devonian - Cambrian unnamed sedimentary rocks (Devonian-Cambrian)
Devonian - Cambrian unnamed sedimentary rocks
Devonian Carrabassett Formation massive pelite member (Devonian)
Devonian Carrabassett Formation massive pelite member
Devonian Carrabassett Formation thinly layered member (Devonian)
Devonian Carrabassett Formation thinly layered member
Devonian Eastport Formation pelite member (Devonian)
Devonian Eastport Formation pelite member
Devonian - Ordovician Dideguash Formation (Devonian - Ordovician)
Devonian - Ordovician Dideguash Formation
Devonian - Ordovician unnamed pelite (Devonian - Ordovician)
Devonian - Ordovician unnamed pelite
Devonian Seboomook Formation (Devonian)
Devonian Seboomook Formation
Devonian Seboomook Formation unnamed pelite (Devonian)
Devonian Seboomook Formation unnamed pelite
Devonian - Silurian Allagash Lake Formation mixed sedimentary rocks (Devonian - Silurian)
Devonian - Silurian Allagash Lake Formation mixed sedimentary rocks
Devonian - Silurian Bell Brook Formation, pelite member (Devonian - Silurian)
Devonian - Silurian Bell Brook Formation pelite member
Devonian - Silurian Calderwood Formation (Devonian - Silurian)
Devonian - Silurian Calderwood Formation
Devonian - Silurian Fish River Lake Formation (Devonian - Silurian)
Devonian - Silurian Fish River Lake Formation
Devonian - Silurian Fogelin Hill Formation (Devonian - Silurian)
Devonian - Silurian Fogelin Hill Formation
Devonian - Silurian Frost Pond Formation (Devonian - Silurian)
Devonian - Silurian Frost Pond Formation
Devonian - Silurian Rindgemere Formation lower member (Devonian - Silurian)
Devonian - Silurian Rindgemere Formation lower member
Devonian - Silurian Rindgemere Formation lower member sulfidic pelite (Devonian - Silurian)
Devonian - Silurian Rindgemere Formation lower member sulfidic pelite
Devonian - Silurian Rindgemere Formation upper member (Devonian - Silurian)
Devonian - Silurian Rindgemere Formation upper member
Devonian - Silurian Towow Formation (Devonian - Silurian)
Devonian - Silurian Towow Formation
Devonian - Silurian undifferentiated sedimentary rocks of the Spider Lake, Chandler Pond and Third Lake Formations (Devonian - Silurian)
Devonian - Silurian undifferentiated sedimentary rocks of the Spider Lake, Chandler Pond and Third Lake Formations
Devonian - Silurian unnamed sedimentary rocks (Devonian - Silurian)
Devonian - Silurian unnamed sedimentary rocks
Devonian Swanback Formation (Devonian)
Devonian Swanback Formation
Devonian unnamed pelite (Devonian)
Devonian unnamed pelite
Devonian unnamed sedimentary rocks (Devonian)
Devonian unnamed sedimentary rocks
Ordovician Benner Hill formation (Ordovician)
Ordovician Benner Hill formation
Ordovician Benner Hill Formation sulfidic pelite (Ordovician)
Ordovician Benner Hill Formation sulfidic pelite
Ordovician Blind Brook Formation (Ordovician)
Ordovician Blind Brook Formation
Ordovician - Cambrian Cookson Formation lithic sandstone and pelite (Ordovician - Cambrian)
Ordovician - Cambrian Cookson Formation lithic sandstone and pelite
Ordovician - Cambrian Cookson Formation sulfidic pelite (Ordovician - Cambrian)
Ordovician - Cambrian Cookson Formation sulfidic pelite
Ordovician - Cambrian Sawmill Formation (Ordovician - Cambrian)
Ordovician - Cambrian Sawmill Formation
Ordovician - Cambrian Southeast Cove Formation (Ordovician - Cambrian)
Ordovician - Cambrian Southeast Cove Formation
Ordovician - Cambrian unnamed sedimentary rocks (Ordovician - Cambrian)
Ordovician - Cambrian unnamed sedimentary rocks
Ordovician Holmes Hole Formation (Ordovician)
Ordovician Holmes Hole Formation
Ordovician Kamankeag Formation pelite member (Ordovician)
Ordovician Kamankeag Formation pelite member
Ordovician Madawaska Lake Formation (Ordovician)
Ordovician Madawaska Lake Formation
Ordovician - Precambrian Z Cushing Formation sulfidic pelite (Ordovician - Precambrian Z)
Ordovician - Precambrian Z Cushing Formation sulfidic pelite
Ordovician - Precambrian Z interbedded pelite and quartz sandstone of the Passagassawakeag block (Ordovician - Precambrian Z)
Ordovician - Precambrian Z interbedded pelite and quartz sandstone of the Passagassawakeag block
Ordovician - Precambrian Z Jewell Formation (Ordovician - Precambrian Z)
Ordovician - Precambrian Z Jewell Formation
Ordovician - Precambrian Z Macworth formation (Ordovician - Precambrian Z)
Ordovician - Precambrian Z Macworth formation
Ordovician - Precambrian Z unnamed sedimentary rocks (Ordovician - Precambrian Z)
Ordovician - Precambrian Z unnamed sedimentary rocks
Ordovician Quimby formation pelite member (Ordovician)
Ordovician Quimby formation pelite member
Ordovician unnamed pelite (Ordovician)
Ordovician unnamed pelite
Ordovician unnamed quartz sandstone and pelite (Ordovician)
Ordovician unnamed quartz sandstone and pelite
Ordovician unnamed sandstone and pelite (Ordovician)
Ordovician unnamed sandstone and pelite
Ordovician unnamed sulfidic pelite (Ordovician)
Ordovician unnamed sulfidic pelite
Precambrian Z North Haven Formation (Precambrian)
Precambrian Z North Haven Formation
Precambrian Z Ogier Point Formation (Precambrian)
Precambrian Z Ogier Point Formation
Precambrian Z rocks of Islesboro (Precambrian Z)
Precambrian Z rocks of Islesboro
Silurian Burnt Brook Formation (Silurian)
Silurian Burnt Brook Formation
Silurian Hardwood Mountain Formation (Silurian)
Silurian Hardwood Mountain Formation
Silurian Jemtland Formation (Silurian)
Silurian Jemtland Formation
Silurian Leighton Formation pelite member (Silurian)
Silurian Leighton Formation pelite member
Silurian Maple Mountain Formation (Silurian)
Silurian Maple Mountain Formation
Silurian New Sweden Formation (Silurian)
Silurian New Sweden Formation
Silurian - Ordovician Carys Mills Formation pelite member (Silurian - Ordovician)
Silurian - Ordovician Carys Mills Formation pelite member
Silurian - Ordovician Mattawamkeag Formation (Silurian - Ordovician)
Silurian - Ordovician Mattawamkeag Formation
Silurian - Ordovician Nine Lake formation (Silurian - Ordovician)
Silurian - Ordovician Nine Lake formation
Silurian - Ordovician unnamed pelite (Silurian - Ordovician)
Silurian - Ordovician unnamed pelite
Silurian - Ordovician unnamed sedimentary rocks (Silurian - Ordovician)
Silurian - Ordovician unnamed sedimentary rocks
Silurian - Ordovician unnamed sulfidic pelite (Silurian - Ordovician)
Silurian - Ordovician unnamed sulfidic pelite
Silurian Quoddy formation pelite member (Silurian)
Silurian Quoddy formation pelite member
Silurian Rangeley formation (Silurian)
Silurian Rangeley formation
Silurian Spragueville Formation (Silurian)
Silurian Spragueville Formation
Silurian unnamed sedimentary rocks (Silurian)
Silurian unnamed sedimentary rocks
Silurian Unnamed sulfidic pelite (Silurian)
Silurian Unnamed sulfidic pelite

Michigan

Minnesota

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.
Cretaceous, undifferentiated (Phanerozoic | Mesozoic | Cretaceous)
Cretaceous, undifferentiated: used in only a few areas, such as the Disturbed Belt east of Glacier National Park, where subdivision in difficult.
Eagle sandstone (Phanerozoic | Mesozoic | Cretaceous-Late)
Eagle sandstone: sandstone and shaly sandstone with lignite beds in basal part of upper unit (Keu). The Virgelle sandstone member (Kvi) at base is distinguished where possible. Near Yellowstone National Park rocks incorrectly called Laramide in early reports and now regarded as roughly equivalent to the Eagle sandstone are tentatively mapped as Eagle sandstone.
Fox Hill sandstone (Phanerozoic | Mesozoic | Cretaceous-Late)
Fox Hills sandstone: Typically shaly sandstone grading upward into massive brownish sandstone with white sandstone of the Colgate member locally at top.
Greenhorn formation (Phanerozoic | Mesozoic | Cretaceous-Late)
Greenhorn formation: mainly light-gray marl and calcareous shale.
Hell Creek formation (Phanerozoic | Mesozoic Cenozoic | Cretaceous-Late Tertiary | Paleocene)
Hell Creek formation: somber-gray sandstone and greenish shaly clay and mudstone containing dinosaur bones; a few thin lignite and subbituminous coal beds.
Judith River formation (Phanerozoic | Mesozoic | Cretaceous-Late)
Judith River formation: light-colored sandstone at top; lower third somber-gray siltstone and sandy shale; greenish-gray clay and some lignite beds; includes the Parkman sandstone member of south-central Montana.
Kootenai formation and associated rocks (Phanerozoic | Mesozoic | Jurassic Cretaceous-Early)
Kootenai formation and associated rocks: conglomerate, sandstone, shale, and mudstone; purplish and green beds are common; mainly the Kootenai; in southern Montana includes strata that have been mapped as Cloverly formation. Includes Second Cat Creek and Third Cat Creek sands of drillers in central part of State; Sunburst sand of drillers in north-central part; and Cut Bank sand of drillers in western part. As here mapped, may locally include thin units of Jurassic age.
Lennep sandstone (Phanerozoic | Mesozoic | Cretaceous-Late)
Lennep sandstone: mainly dark-brown andesitic sandstone with intercalated shale; locally contains thin coal beds.
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.
St. Mary River formation (Phanerozoic | Mesozoic | Cretaceous-Late)
St. Mary River formation: Greenish-gray clay with local nodular limestone and crossbedded sandstone.
Telegraph Creek formation (Phanerozoic | Mesozoic | Cretaceous-Late)
Telegraph Creek formation: buff mainly soft, fissile sandy shale with subordinate amounts of concretionary sandstone.
Thermopolis shale (Phanerozoic | Mesozoic | Cretaceous-Early)
Thermopolis shale: dark-gray shale with some sandstone. The subsurface consists of Muddy sandstone member or Newcastle sandstone member at top, Skull Creek shale member in middle, and Fall River sandstone or First Cat Creek sand of drillers at base.
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

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.
Cape Fear Formation (Cretaceous)
Cape Fear Formation - sandstone and sandy mudstone, yellowish gray to bluish gray, mottled red to yellowish orange, indurated, graded and laterally continuos bedding, blocky clay, faint cross-bedding, feldspar and mica common.
Middendorf Formation (Cretaceous)
Middendorf Formation - sand, sandstone, and mudstone, gray to pale gray with an orange cast, mottled; clay balls and iron-cemented concretions common, beds laterally discontinuous, cross-bedding common.
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; Cumnock Formation (Triassic)
Cumnock Formation - sandstone and mudstone, gray to black; coal beds and carbonaceous shale. Grades into Pekin and Sanford formations.
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; Cow Branch Formation (Triassic)
Cow Branch Formation - mudstone with minor sandstone, gray, laterally-continuous bedding. Intertongues with Stoneville and Pine Hall formations.
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.

Nebraska

New Jersey

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).
Feltville Formation (Lower Jurassic)
Feltville Formation (Olsen, 1980) - Interbedded brownish-red to light-grayish-red, fine- to coarse-grained sandstone, gray and black, coarse siltstone in upward-fining cycles, and silty mudstone. Fine-grained sandstone and siltstone are moderately well sorted, commonly cross-laminated, and have 15 percent or more feldspar; interbedded with brownish-red, indistinctly laminated, bioturbated calcareous mudstone. Thermally metamorphosed into hornfels where in contact with Preakness Basalt. Near the base are two thin, laterally continuous beds of black, carbonaceous limestone and gray, calcareous siltstone, each up to 3 m (10 ft) thick. These contain abundant fish, reptile, anthropod, and diagnostic plant fossils. Three or four, thin, gray to black siltstone and mudstone sequences occur in upper part of unit. 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. Maximum thickness about 155 m (510 ft).
Feltville Formation (Lower Jurassic)
Feltville Formation - Mostly fine-grained, feldspathic sandstone, coarse siltstone, and silty mudstone, brownish-red to light-grayish-red. Fine-grained sandstone is moderately well sorted, cross laminated, and contains 15 percent or more feldspar; interbedded with mudstone, indistinctly laminated, bioturbated, and calcareous in places. A thin bed (0-2 m (0-7 ft) thick) of black, microlaminated carbonaceous limestone and gray calcareous mudstone occurs near the base and contains fish and plant fossils, and thermally mature hydrocarbons. Thickness of unit in the Sand Brook syncline is about 155 m (509 ft).
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 (Upper Triassic)
Lockatong Formation (Kummel, 1897) - Cyclically-deposited sequences consisting of light- to dark-gray, greenish-gray, and black, dolomitic or analcime-bearing silty argillite, laminated mudstone, silty to calcareous, argillaceous, very-fine-grained pyritic sandstone and siltstone, and minor silty limestone (Trl). Grayish-red, grayish-purple, and dark-brownish-red sequences (Trlr) common in upper half. Two types of cycles are recognized: detrital and chemical. Detrital cycles average 5.2 m (17 ft) thick and consist of basal, argillaceous, very fine grained sandstone to coarse siltstone; medial, dark-gray to black, laminated siltstone, silty mudstone, or silty limestone; and upper, light- to dark-gray, silty to dolomitic or analcime-rich mudstone, argillitic siltstone, or very-fine-grained sandstone. Chemical cycles are similar to detrital cycles, but thinner, averaging 3.2 m (10.5 ft). Cycles in northern Newark basin are thinner and have arkosic sandstone in lower and upper parts. Upper part of formation in northern basin composed mostly of light-gray to light-pinkish-gray or light-brown, coarse- to fine-grained, thick- to massive-bedded arkosic sandstone (Trla). Thermally metamorphosed into hornfels where intruded by diabase (Jd). Interfingers laterally and gradationally with quartz sandstone and conglomerate (Trls) and quartzite conglomerate (Trlcq) near Triassic border fault in southwestern area of map. Maximum thickness of Lockatong Formation about 1,070 m (3,510 ft).
Lockatong Formation (Upper Triassic)
Lockatong Formation - Predominantly cyclic lacustrine sequences of silty, dolomitic or analcime-bearing argillite; laminated mudstone; silty to calcareous, argillaceous very fine grained sandstone and pyritic siltstone; and minor silty limestone, mostly light- to dark-gray, greenishgray, and black. Grayish-red, grayish-purple, and dark-brownish-red sequences (Trlr) occur in some places, especially in upper half. Two types of cycles are recognized: freshwater-lake (detrital) and alkaline-lake (chemical) cycles. Freshwater-lake cycles average 5.2 m (17 ft) thick. They consist of basal, transgressive, fluvial to lake-margin deposits that are argillaceous, very fine grained sandstone to coarse siltstone with indistinct lamination, planar or cross lamination, or are disrupted by convolute bedding, desiccation cracks, root casts, soil-ped casts, and tubes. Medial lake-bottom deposits are laminated siltstones, silty mudstones, or silty limestones that are dark gray to black with calcite laminae and grains and lenses, or streaks of pyrite; fossils are common, including fish scales and articulated fish, conchostracans, plants, spores, and pollen. Upper regressive lake margin, playa lake, and mudflat deposits are light- to dark-gray silty mudstone to argillitic siltstone or very fine grained sandstone, mostly thick bedded to massive, with desiccation cracks, intraformational breccias, faint wavy laminations, burrows, euhedral pyrite grains, and dolomite or calcite specks. Alkaline-lake cycles are similar to freshwater-lake cycles, but are thinner, averaging 3 m (10 ft), have fewer fossils (mainly conchostracans), and commonly have red beds, extensive desiccation features, and abundant analcime and dolomite specks in the upper parts of cycles. Thickness near Byram is about 1,070 m (3,510 ft). The formation thins to the southeast and northeast; thickness near Princeton is less than 700 m (2,297 ft).
Lockatong Formation red bed (Upper Triassic)
Lockatong Formation red bed - Cyclically-deposited sequences consisting of light- to dark-gray, greenish-gray, and black, dolomitic or analcime-bearing silty argillite, laminated mudstone, silty to calcareous, argillaceous, very-fine-grained pyritic sandstone and siltstone, and minor silty limestone (Trl). Grayish-red, grayish-purple, and dark-brownish-red sequences (Trlr) common in upper half.
Lockatong Formation red bed (Upper Triassic)
Lockatong Formation red bed - Predominantly cyclic lacustrine sequences of silty, dolomitic or analcime-bearing argillite; laminated mudstone; silty to calcareous, argillaceous very fine grained sandstone and pyritic siltstone; and minor silty limestone, mostly light- to dark-gray, greenishgray, and black. Grayish-red, grayish-purple, and dark-brownish-red sequences (Trlr) occur in some places, especially in upper half. Two types of cycles are recognized: freshwater-lake (detrital) and alkaline-lake (chemical) cycles. Freshwater-lake cycles average 5.2 m (17 ft) thick. They consist of basal, transgressive, fluvial to lake-margin deposits that are argillaceous, very fine grained sandstone to coarse siltstone with indistinct lamination, planar or cross lamination, or are disrupted by convolute bedding, desiccation cracks, root casts, soil-ped casts, and tubes. Medial lake-bottom deposits are laminated siltstones, silty mudstones, or silty limestones that are dark gray to black with calcite laminae and grains and lenses, or streaks of pyrite; fossils are common, including fish scales and articulated fish, conchostracans, plants, spores, and pollen. Upper regressive lake margin, playa lake, and mudflat deposits are light- to dark-gray silty mudstone to argillitic siltstone or very fine grained sandstone, mostly thick bedded to massive, with desiccation cracks, intraformational breccias, faint wavy laminations, burrows, euhedral pyrite grains, and dolomite or calcite specks. Alkaline-lake cycles are similar to freshwater-lake cycles, but are thinner, averaging 3 m (10 ft), have fewer fossils (mainly conchostracans), and commonly have red beds, extensive desiccation features, and abundant analcime and dolomite specks in the upper parts of cycles. Thickness near Byram is about 1,070 m (3,510 ft). The formation thins to the southeast and northeast; thickness near Princeton is less than 700 m (2,297 ft).
Passaic Formation gray bed (Lower Jurassic and Upper Triassic)
Passaic Formation gray bed - Rhythmic cycles 2 to 7 m (7-23 ft) of thick gray-bed sequences (Trpg), termed Van Houten cycles by Olsen (1985), contain basal thin-bedded to finely laminated shale to siltstone, which grade upward through laminated to micro-laminated, locally calcareous mudstone to siltstone and finally into massive silty mudstone. Lowest part of cycle has some desiccation features and local fossils; middle part has highest organic content and the most fossils; highest part contains mudcracks, burrows, and root casts. Gray-bed cycles are abundant in lower half of Passaic Formation and less common in upper half.
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.
Stockton Formation (Upper Triassic)
Stockton Formation (Kummel, 1897) - Light-gray, light-grayishbrown, yellowish- to pinkish-gray, or violet-gray to reddish-brown, medium- to coarse-grained arkosic sandstone and reddish- to purplish-brown mudstone, silty mudstone, argillaceous siltstone, and shale. Mudstone, siltstone and shale beds thicker and more numerous in central Newark basin west of Round Valley Reservoir. Sandstones mostly planar-bedded, with scoured bases containing pebble lags and mudstone rip-ups. 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). Maximum thickness of formation about 1,240 m (4,070 ft).

New Mexico

Bull Canyon Formation of Chinle Group (Phanerozoic | Mesozoic | Triassic)
Bull Canyon Formation; Norian
Garita Creek Formation of Chinle Group (Phanerozoic | Mesozoic | Triassic)
Garita Creek Formation; Carnian
Grayburg and Queen Fromations (Phanerozoic | Paleozoic | Permian)
Grayburg and Queen Formations; sandstone, gypsum, anhydrite, dolomite, and red mudstone; Guadalupian
Kirtland and Fruitland Formations (Phanerozoic | Mesozoic | Cretaceous)
Kirtland and Fruitland Formations; coal-bearing, coal primarily in the Fruitland; Campanian to Maastrichtian
Moenkopi Formation (Phanerozoic | Mesozoic | Triassic)
Moenkopi Formation; Middle Triassic
Pictured Cliffs Sandstone (Phanerozoic | Mesozoic | Cretaceous)
Pictured Cliffs Sandstone; prominent cliff-forming marine sandstone
Poison Canyon and Raton Fromations (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Poison Canyon and Raton Formations; undivided
Quartermaster Formation (Phanerozoic | Paleozoic | Permian)
Quartermaster Formation; red sandstone and siltstone; Upper Permian
Quatermaster and Rustler Formations (Phanerozoic | Paleozoic | Permian)
Quartermaster and Rustler Formations; Upper Permian
Raton Formation (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary)
Raton Formation; in Raton Basin; unit contains conformable K/T boundary
Redonda Formation of Chinle Group (Phanerozoic | Mesozoic | Triassic)
Redonda Formation
Santa Rosa Formation of Chinle Group (Phanerozoic | Mesozoic | Triassic)
Santa Rosa Formation; Carnian; includes Moenkopi Formation (Middle Triassic) at base in most areas
Yesa Formation (Phanerozoic | Paleozoic | Permian)
Yeso Formation; sandstones, siltstones, anhydrite, gypsum, halite, and dolomite; Leonardian

Nevada

New York

Ohio

Conemaugh Group (Pennsylvanian)
Conemaugh Group - Shale, siltstone, and mudstone: Shale, black, gray, green and red; clayey to silty; locally contains marine fossils in lower half of unit; calcareous in part. Siltstone, gray, green and red, locally variegated; clayed to sandy; thin bedded to nonbedded. Mudstone, black, gray, green, red, and yellow, variegated in part; clayey to silty; locally calcareous; commonly nonbedded. Sandstone, green-gray weathers to shades of yellow-brown; mostly very fine to medium grained, locally conglomeratic; thin to massive to cross bedded; locally calcareous. Limestone and coal; thin and discontinuous. Limestone, black, gray and green; micritic to coarse grained; thin bedded to concretionary with marine fossils common in lower half of interval; thin to medium bedded, nonmarine limestone common in upper half of unit. Coal, thin, bituminous, impure; very locally thick enough for economic development. Lateral and vertical lithic variability and gradation common. Unit as much as 500 feet thick.
Dunkard Group (Permian and/or Pennsylvanian)
Dunkard Group - Mudstone, shale, and siltstone (60-70 percent); shades of red, yellow, olive, and/or brown in southern areas of Ohio to gray, green and black in northern areas; clayey to sandy; nonbedded to thin bedded; locally calcareous. Sandstone (25-35 percent); blue-gray weathers to shades of yellow-brown; fine grained to locally conglomeratic; thin to massive to cross bedded. Limestone and coal (5 percent): Limestone, gray, micritic, clayey to silty, thin to medium bedded in northern areas of Ohio, nodular bedded to argillaceous in southern areas. Coal, black, banded, thin, discontinuous, impure; poorly developed in southern areas of Ohio. Limestones and coals best developed in lower 90 to 200 feet. Lateral and vertical lithic variability and gradation common. Unit greater than 600 feet thick in southeast Ohio.
Monongahela Group (Pennsylvanian)
Monongahela Group - Shale, siltstone, and mudstone; black, red, gray and green to variegated red and yellow in the southeastern areas of Ohio; clayey to sandy; nonbedded to thin bedded; locally calcareous. Sandstone, greenish-gray weathers to shades of yellow-brown, silty to locally conglomeratic; thin to massive to cross bedded; locally calcareous. Limestone, gray, micritic, clayey to silty, thin to medium bedded; generally more common in middle and lower portions of unit. Coal, banded, bituminous, thin to as much as 8 feet thick in central and northern areas, thinner to absent in southeastern Ohio. Lateral and vertical lithic variability and gradation common. Unit as much as 350 feet thick.

Oklahoma

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.
Denton Clay (Phanerozoic | Mesozoic | Cretaceous-Early )
McALESTER TEXARKANA- Clay and shale, blue- to brownish-gray, and marly, fossiliferous limestone with "Texigryphaea washitaensis;" thickness, 45 to 65 feet.
Elk City Sandstone (Phanerozoic | Paleozoic | Permian )
CLINTON- Reddish-brown, fine-grained sandstone with minor amounts of silt and clay, weakly cemented by iron oxide, calcium carbonate, and gypsum; maximum thickness 185 feet, top eroded.
Goodland Limestone and Walnut Clay (Phanerozoic | Mesozoic | Cretaceous-Early )
ARDMORE-SHERMAN- "Goodland Limestone," limestone, gray, dense, nodular to massive; thickness, 20 to 30 feet. At base is "Walnut Clay," tan clay, about 4 feet thick. McALESTER TEXARKANA- Limestone, white, fine crystalline, massive-bedded, with "Texigryphaea mucronata;" some argillaceous buff beds in lower few feet may be "Walnut Clay" equivalents; erodes into a mappable escarpment; thickness, 26 to 55 feet.
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
Weno Clay and Soper Limestone (Phanerozoic | Mesozoic | Cretaceous-Early )
McALESTER TEXARKANA- "Weno Clay", clay and shale, brownish-gray, with selenite gypsum; interbedded with red- to yellow-brown fine-grained sandstones; thickness, 30 to 53 feet. "Soper Limestone" at base, limestone, gray-brown to red-brown, compact, fossiliferous, with "Rastellum carinatum;" thickness, 1 to 2 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
John Day Formation of east-central Oregon (lower Miocene, Oligocene, and uppermost Eocene?) (Late Eocene to Early Miocene)
Marine sandstone and siltstone (middle Eocene) (Middle Eocene)
Thin- to thick-bedded, crossbedded, well-sorted, fine- to medium-grain sandstone, siltstone, and mudstone; characterized by sparse fine white mica; shallow marine depositional setting at least partly of deltaic origin. Contains foraminiferal and molluscan faunas of early middle Eocene age. Included by Diller (1898) in the upper part of the Umpqua Formation, by Baldwin (1974) and Ryberg (1984) in the Flournoy Formation of the Umpqua Group, and by Molenaar (1985) in Camas Valley and the White Tail Ridge Members of Baldwin (1974) of the Umpqua Formation
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 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)
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 rocks (Jurassic) (Late Jurassic )
Black and gray mudstone, shale, siltstone, graywacke, andesitic to dacitic water-laid tuff, porcelaneous tuff, and minor interlayers and lenses of limestone and fine-grained sediments metamorphosed to phyllite or slate. Locally includes some felsite, andesite and basalt flows, breccia, and agglomerate. Marine invertebrate fauna indicates age range from Early Jurassic (Hettangian) to early Late Jurassic (Oxfordian). In Klamath Mountains of southwest Oregon, includes Galice Formation (Wells and Peck, 1961) and unnamed, hornblende- and (or) pyroxene-bearing clastic rocks of Jurassic age (Smith and others, 1982)
Sedimentary rocks (Jurassic and Upper Triassic) (Triassic to Jurassic)
Black, dark-gray, and dark -brownish-gray, thin-bedded siliceous or limy mudstone mostly consists of the Hurwal Formation in the Wallowa Mountains. In lower and middle parts contains Triassic fossils and in upper part Early Jurassic fossils (Nolf, 1966). Contact metamorphosed adjacent to Wallowa batholith
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 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, 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
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)
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)
Tuffaceous siltstone and sandstone (upper and middle Eocene) (Middle Eocene to Late Eocene)
Thick- to thin-bedded marine tuffaceous mudstone, siltstone, and sandstone; fine to coarse grained. Contains calcareous concretions and, in places, is carbonaceous and micaceous. Includes the Nestucca Formation, which contains a foraminiferal assemblage assigned to the upper Narizian and lowermost Refugian Stages (Snavely and others, 1969; McKeel, 1980); the Spencer Formation, which contains Narizian Stage foraminifers; the Keasey Formation, which contains upper Narizian and lower Refugian Stage foraminifers (McDougall, 1975, 1980); the Coaledo and Bateman Formations of Baldwin (1974); upper Eocene sandstone of Bela (1981); and the Sager Creek formation (informal name) of Niem and Niem (1985)
Ultramafic and related rocks of ophiolite sequences; Basaltic volcanic and sedimentary rocks (Jurassic) (Jurassic)
Basalt flows, flow breccia, agglomerate, pillow basalt and pillow breccia, and lesser shale, chert, siltstone, and mudstone of ophiolitic complexes
Volcanic rocks (Jurassic) (Late Jurassic)
Lava flows, flow breccia, and agglomerate dominantly of plagioclase, pyroxene, and hornblende porphyritic and aphyric andesite. Includes flow rocks that range in composition from basalt to rhyolite as well as some interlayered tuff and tuffaceous sedimentary rocks. Commonly metamorphosed to greenschist facies; locally foliated, schistose or gneissic. Includes the Rogue Formation and volcanic rocks commonly assigned to the Galice Formation (Wells and Walker, 1953; Wells and Peck, 1961). Considered to be accreted island-arc terrane
Welded tuffs and tuffaceous sedimentary rocks (upper? and middle Miocene) (Middle to Late Miocene)
Partly to densely welded vitric and vitric-crystal tuff of soda-rhyolitic, rhyolitic, and rhyodacitic composition that interfingers with and grades laterally into unit Tit. Includes some nonwelded ash-flow tuff and tuffaceous sedimentary rocks. Potassium-argon ages range from about 13 to 16 Ma. In Harney and Malheur Counties, it commonly overlies unit Tmb. Includes Dinner Creek Welded Tuff of Haddock (1965; 1967) and middle and upper Miocene ash-flow tuffs of Rytuba and others (1982; 1983a, b), widely exposed in the Trout Creek Mountains and adjacent areas, erupted from the McDermitt caldera complex, west and southwest of McDermitt, Nevada-Oregon, the White Horse caldera, northwest of McDermitt, and several other vent areas

Pennsylvania

Berry Run and Sawmill Run Members of Catskill Formation, undivided (Devonian)
Berry Run and Sawmill Run Members of Catskill Formation, undivided - Greenish-gray to gray sandstone and minor red siltstone and mudstone.
Bloomsburg and Mifflintown Formations, undivided (Silurian)
Bloomsburg and Mifflintown Formations, undivided - Includes, in descending order, the Bloomsburg Formation (Sb) and the Mifflintown Formation--interbedded dark-gray shale and medium-gray fossiliferous limestone; equivalent to "McKenzie" and "Rochester" of earlier workers; not present east of Harrisburg.
Bloomsburg Formation (Silurian)
Bloomsburg Formation - Grayish-red and greenish-gray shale, siltstone, and very fine to coarse-grained sandstone; some calcareous mudstone in central Pennsylvania; thins to west and is replaced by Mifflintown beds; thickens eastward, replacing overlying Wills Creek and Tonoloway Formations and underlying Mifflintown Formation.
Brunswick Formation (Triassic)
Brunswick Formation - Reddish-brown mudstone, siltstone, and shale, containing a few green and brown shale interbeds; red and dark-gray, interbedded argillites near base. Youngest beds in Brunswick may be Jurassic in age.
Buddys Run Member of Catskill Formation (Devonian)
Buddys Run Member of Catskill Formation - Grayish-red and brownish-gray siltstone, mudstone, and sandstone; some gray and dusky-yellow sandstone and siltstone; laterally equivalent to Duncannon, Clarks Ferry, and Sherman Creek Members.
Catskill Formation (Devonian)
Catskill Formation - Succession of grayish-red sandstone, siltstone, shale, and mudstone, generally in fining-upward cycles; some gray sandstone and conglomerate.
Catskill Formation (Devonian)
Catskill Formation - Grayish-red sandstone, siltstone, shale, and mudstone; units of gray sandstone occur in upper part; lithologies in upper part arranged in fining-upward cycles. In the Altoona area, the Catskill Formation is mapped as the Duncannon, Sherman Creek, and Irish Valley Members, which are described under "Central and Eastern Pennsylvania" provinces.
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.
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.
Gettysburg conglomerate (Triassic)
Gettysburg conglomerate - Gray quartz conglomerate, sandstone, and red siltstone and mudstone.
Gettysburg Formation (Triassic)
Gettysburg Formation - Reddish-brown to maroon, silty mudstone and shale containing thin red sandstone interbeds; several thin beds of impure limestone.
Hammer Creek Formation (Triassic)
Hammer Creek Formation - Gray and pale red, fine- to coarse-grained quartzose sandstone, siltstone, and mudstone.
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.
Keyser Formation through Clinton Group, undivided (Devonian and Silurian)
Keyser Formation through Clinton Group, undivided - Same as Keyser-through-Mifflintown (DSkm) interval, plus Clinton Group at base. Clinton includes the following, in descending order: Keefer Formation--fossiliferous sandstone and hematitic, oolitic sandstone and shale; Rose Hill Formation--fossiliferous shale.
Keyser Formation through Mifflintown Formation, undivided (Devonian and Silurian)
Keyser Formation through Mifflintown Formation, undivided - In descending order: Keyser Formation--limestone; Tonoloway Formation--limestone and interbedded shale; Wills Creek Formation--interbedded shale, siltstone, limestone, and dolomite; Bloomsburg Formation--grayish-red and greenish-gray shale, siltstone, sandstone, and mudstone; Mifflintown Formation--interbedded shale and limestone.
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.
Long Run and Walcksville Members of Catskill Formation, undivided (Devonian)
Long Run and Walcksville Members of Catskill Formation, undivided - Includes, in descending order, the Long Run (Dclr) and Walcksville (Dcw) Members of the Catskill Formation, which are described separately below.
Long Run Member of Catskill Formation (Devonian)
Long Run Member of Catskill Formation - Gray and grayish-red sandstone and grayish-red siltstone and mudstone in fining-upward cycles.
New Oxford Formation (Triassic)
New Oxford Formation - Light-gray to buff, commonly arkosic sandstone interbedded with red shale, mudstone, and fine-grained sandstone
Scherr Formation (Devonian)
Scherr Formation - Chiefly siltstone; some fine-grained sandstone, shale, and mudstone; light olive gray; marine fossils.
Sherman Creek Member of Catskill Formation (Devonian)
Sherman Creek Member of Catskill Formation - Alternating grayish-red mudstone and siltstone in poorly defined fining-upward cycles, and minor intervals of gray sandstone; laterally equivalent to Berry Run, Sawmill Run, Packerton, and Long Run Members of eastern Pennsylvania.
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 Formation (Triassic)
Stockton Formation - Light-gray to buff, coarse-grained, arkosic sandstone; includes reddish-brown to grayish-purple sandstone, siltstone, and mudstone.
Walcksville and Towamensing Members of Catskill Formation, undivided (Devonian)
Walcksville and Towamensing Members of Catskill Formation, undivided - Includes, in descending order, the Walcksville Member (Dcw) of the Catskill Formation, and the Towamensing Member (Dct).
Walcksville Member of Catskill Formation (Devonian)
Walcksville Member of Catskill Formation - Greenish-gray sandstone and red siltstone and mudstone in fining-upward cycles.
Wills Creek Formation through Mifflintown Formation, undivided (Silurian)
Wills Creek Formation through Mifflintown Formation, undivided - Includes, in descending order, the Wills Creek Formation (Swc) and Bloomsburg and Mifflintown Formations, undivided (Sbm).

South Carolina

South Dakota

Greenhorn Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
Gray shale, mudstone, marl, calcarenite, and shaley limestone grading upward into light-gray to tan, alternating marl and thin-bedded, fossiliferous limestone. Thickness 225-315 ft (69-96 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
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).

Tennessee

Sequatchie Formation, Leipers Formation, Inman Formation and Catheys Formation (Ordovician)
Sequatchie Formation - Greenish-gray calcareous shale, mudstone, and argillaceous limestone; dolomitic, laminated, and sandy. Thickness 0 to 165 feet; Leipers Formation - Nodular, shaly limestone and fine- to coarse-grained limestone. Thickness 0 to 150 feet; Inman Formation - Thin-bedded to laminated, fine-grained, greenish-gray limestone interbedded with red and green calcareous shale beds. Thickness 0 to 50 feet. (Present only in Sequatchie Valley.); and Catheys Formation - Nodular, shaly, thin- to medium-bedded limestone and fine- to coarse-grained limestone. Thickness 125 to 400 feet.
Silurian Formations, including Decatur Limestone, Brownsport Group (Lobelville Formation, Bob Limestone, Beech River Formation), Wayne Group (Dixon Formation, Lego Formation, Waldron Shale, Laurel Limestone, Osgood Formation) and Brassfield Limestone (Silurian)
Silurian Formations - A complete section of Silurian formations is not common because of pre-Chattanooga and/or pre- Cretaceous erosion. Where preserved, Silurian formations are remarkably uniform in thickness and are characteristically light olive-gray to greenish-gray with variable reddish-brown color in some area;. Decatur Limestone - Thick-bedded, medium- to coarse-grained limestone, gray with reddish-brown grains. Thickness 0 to 70 feet; Brownsport Group which includes 1) Lobelville Formation - Shale with thin beds of limestone. Thickness 0 to 40 feet; 2) Bob Limestone - Thick-bedded, medium-grained limestone, locally oolitic. Thickness 0 to 25 feet; and 3) Beech River Formation - Shale with thin beds of limestone. Thickness 0 to 60 feet; Wayne Group which includes: 1) Dixon Formation - Green and reddish-brown argillaceous limestone, shale, and mudstone. Thickness 0 to 40 feet; 2) Lego Limestone - Even-bedded, olive-gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; 3) Waldron Shale - Greenish-gray fossiliferous shale. Thickness 0 to 5 feet; 4) Laurel Limestone - Even-bedded, gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; 5) Osgood Formation - Greenish- and reddish-gray shale and argillaceous limestone. Thickness 0 to 15 feet.; and Brassfield Limestone - Thin-bedded cherty limestone, locally glauconitic. Thickness 0 to 20 feet.
Silurian Formations, including Decatur Limestone, Brownsport Group (Lobelville Formation, Bob Limestone, Beech River Formation), Wayne Group (Dixon Formation, Lego Formation, Waldron Shale, Laurel Limestone, Osgood Formation) and Brassfield Limestone (Silurian)
Silurian Formations - Characteristically light olive-gray to greenish-gray, with variable reddish-brown color in some areas. Individual formations are generally uniform in thickness, except where truncated by pre- Chattanooga erosion. Most formations are slightly thicker (than indicated) in Wells Creek Basin. Includes Decatur Limestone- Thick-bedded, medium- to coarse-grained limestone, gray with reddish-brown grains. Thickness 0 to 70 feet; Brownsport Group ( which includes Lobelville Formation - Shale with thin beds of limestone. Thickness 0 to 30 feet; Bob Limestone - Thick-bedded, medium-grained limestone, locally oolitic. Thickness 0 to 25 feet; and Beech River Formation - Shale with thin beds of limestone. Thickness 0 to 60 feet); Wayne Group (which includes Dixon Formation - Green and reddish-brown argillaceous limestone, shale, and mudstone. Thickness 0 to 40 feet; Lego Limestone - Even-bedded, olive-gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; Waldron Shale - Greenish-gray fossiliferous shale. Thickness 0 to 5 feet; Laurel Limestone - Even-bedded, olive-gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; Osgood Formation - Greenish- and reddish-gray shale and argillaceous limestone. Thickness 0 to 15 feet); and Brassfield Limestone - Thin-bedded cherty limestone, locally glauconitic. Thickness 0 to 50 feet; generally about 20 feet.

Texas

Admiral and Coleman Junction Formations, undivided (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Admiral and Coleman Junction Formations, undivided
Admiral Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Admiral Formation
Anacacho Limestone (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian])
Anacacho Limestone
Archer City Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Archer City Formation
Austin Chalk (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian])
Austin Chalk
Blaine Formation (Phanerozoic | Paleozoic | Permian [Guadalupe])
Blaine Formation
Bonham Formation (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian])
Bonham Formation
Bouquillas Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
Bouquillas Formation
Buda Limestone and Del Rio Clay, undivided (Phanerozoic | Mesozoic | Cretaceous-Late)
Buda Limestone and Del Rio Clay, undivided
Buda Limestone and Eagle Mountain Sandstone, undivided (Phanerozoic | Mesozoic | Cretaceous-Late)
Buda Limestone and Eagle Mountain Sandstone, undivided
Calvert Bluff Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)
Calvert Bluff Formation
Campagrande Formation (Phanerozoic | Mesozoic | Cretaceous-Early)
Campagrande 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
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
Clear Fork Group (Phanerozoic | Paleozoic | Permian [Leonard])
Clear Fork Group
Coleman Junction Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Coleman Junction Formation
Comanchean rocks, undivided (Phanerozoic | Mesozoic | Cretaceous-Early [Washita])
Comanchean rocks, undivided
Cretaceous rocks, undivided (Phanerozoic | Mesozoic | Cretaceous-Late)
Cretaceous rocks, 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.
Del Rio Clay (Phanerozoic | Mesozoic | Cretaceous-Late)
Del Rio Clay
Elm Creek Formation (Phanerozoic | Paleozoic | Permian [Leonard])
Elm Creek Formation
Fort Worth Limestone and Duck Creek Formation, undivided (Phanerozoic | Mesozoic | Cretaceous-Early)
Fort Worth Limestone and Duck Creek Formation, undivided
Fredericksburg Group (Phanerozoic | Mesozoic | Cretaceous-Early [Comanchean])
Fredericksburg Group
Georgetown Limestone (Phanerozoic | Mesozoic | Cretaceous-Early)
Georgetown Limestone
Goliad Formation (Phanerozoic | Cenozoic | Tertiary | Miocene)
Goliad Formation
Grayson Marl and Main Street Limestone, undivided (Phanerozoic | Mesozoic | Cretaceous-Early Cretaceous-Late)
Grayson Marl and Main Street Limestone, undivided
Gulfian rocks, undivided (Phanerozoic | Mesozoic | Cretaceous-Late)
Gulfian rocks, undivided
Harpersville Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian [Virgil])
Harpersville Formation
Hooper Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene)
Hooper Formation
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
Jagger Bend and Valera Formations, undivided (Phanerozoic | Paleozoic | Permian [Leonard])
Jagger Bend and Valera Formations, undivided
lower part of Washita Group (Phanerozoic | Mesozoic | Cretaceous-Early [Comanchean])
lower part of Washita Group
Markley Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian)
Markley Formation
Midway Group, undivided (Phanerozoic | Cenozoic | Tertiary | Paleocene)
Midway Group, undivided
Moodys Branch Formation (Phanerozoic | Cenozoic | Tertiary | Eocene-Late)
Moodys Branch Formation
Moran Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Moran Formation
Nocona Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp Leonard])
Nocona Formation
Pawpaw Formation and upper limestone unit of Weno Formation, undivided (Phanerozoic | Mesozoic | Cretaceous-Early)
Pawpaw Formation and upper limestone unit of Weno Formation, undivided
Pawpaw Formation, Weno Limestone, and Denton Clay, undivided (Phanerozoic | Mesozoic | Cretaceous-Early)
Pawpaw Formation, Weno Limestone, and Denton Clay, undivided
Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation (Phanerozoic | Cenozoic | Tertiary | Oligocene)
Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation
pre-Brazos River rocks, undivided (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian [Des Moines])
pre-Brazos River rocks, undivided
Pueblo Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Pueblo Formation
Salmon Peak Limestone (Phanerozoic | Mesozoic | Cretaceous-Early)
Salmon Peak Limestone
San Angelo Formation (Phanerozoic | Paleozoic | Permian [Guadalupe])
San Angelo Formation
Santa Anna Branch Shale (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Santa Anna Branch Shale
Santa Anna Branch Shale and Sedwick and Moran Formations, undivided (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Santa Anna Branch Shale and Sedwick and Moran Formations, undivided
Santa Elena Limestone (Phanerozoic | Mesozoic | Cretaceous-Early)
Santa Elena Limestone
Sedwick and Moran Formations, undivided (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Sedwick and Moran Formations, undivided
Sedwick Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp])
Sedwick Formation
Simsboro Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene)
Simsboro Formation
Sue Peaks Formation (Phanerozoic | Mesozoic | Cretaceous-Early)
Sue Peaks Formation
Thrifty and Graham Formations, undivided (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Virgil])
Thrifty and Graham Formations, undivided
Torcer Formation (Phanerozoic | Mesozoic | Cretaceous-Early)
Torcer Formation
undivided part Fredericksberg Group (Phanerozoic | Mesozoic | Cretaceous-Early)
undivided part Fredericksberg Group
undivided part of Washita Group (Phanerozoic | Mesozoic | Cretaceous-Early [Comanchean])
undivided part of Washita Group
undivided parts of Washita and Fredericksberg Groups (Phanerozoic | Mesozoic | Cretaceous-Early)
undivided parts of Washita and Fredericksberg Groups
upper Cretaceous rocks, undivided (Phanerozoic | Mesozoic | Cretaceous-Late)
upper Cretaceous rocks, undivided
Waggoner Ranch Formation (Phanerozoic | Paleozoic | Permian [Leonard])
Waggoner Ranch Formation
Wilke Ranch Formation (Phanerozoic | Paleozoic | Permian [Leonard])
Wilke Ranch Formation
Wolfe City Formation (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian])
Wolfe City Formation

Utah

Cambrian quartzite in Logan-Huntsville Allochthon (Early to Middle Cambrian)
Cretaceous (2) sedimentary rocks in central Utah (Cretaceous)
Cretaceous (2) sedimentary rocks in Logan-Huntsville Allochthon (Late Cretaceous)
Cretaceous (2) sedimentary rocks in southwestern Utah (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 and Tertiary sedimentary rocks in Logan-Huntsville Allochthon (Late Cretaceous to Paleocene)
Cretaceous and Tertiary sedimentary rocks in Salt Lake City-Coalville-Randolph region (Late Cretaceous to Paleocene)
Devonian sedimentary rocks in Logan-Huntsville Allochthon (Devonian)
Devonian sedimentary rocks in western Utah (Devonian to Mississippian)
Jurassic (1) sedimentary rocks in central Utah (Middle Jurassic)
Jurassic (1) sedimentary rocks in southeastern Utah (Middle Jurassic)
Jurassic (1) sedimentary rocks in southeastern Utah (Middle to Late Jurassic)
Jurassic (1) sedimentary rocks in Uinta Mountains-Uinta Basin region (Middle to Late Jurassic)
Jurassic (2) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Late Jurassic)
Mississippian (2) sedimentary rocks in central Utah (Mississippian)
Mississippian (2) sedimentary rocks in Logan-Huntsville Allochthon (Mississippian)
Older Precambrian metamorphic rocks in southeastern Utah (Precambrian)
Permian (2) sedimentary rocks in central Utah (Permian)
Tertiary (1) sedimentary rocks in central Utah (Late Paleocene 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 (3) sedimentary rocks in central Utah (Late Eocene to Early Oligocene)
Tertiary (3) sedimentary rocks in southeastern Utah (Eocene)
Tertiary (3) sedimentary rocks in Uinta Mountains-Uinta Basin region (Middle Eocene to Early Oligocene)
Tertiary (4) sedimentary rocks in Logan-Huntsville Allochthon (Middle Miocene to Late Pliocene)
Tertiary (4) sedimentary rocks in northwestern Utah (Middle Miocene to Late Pliocene)
Tertiary (4) sedimentary rocks in southeastern Utah (Late Eocene)
Triassic (1) sedimentary rocks in Logan-Huntsville Allochthon (Early Triassic)
Triassic (1) sedimentary rocks in Salt central Utah (Early Triassic)
Triassic (1) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Early Triassic)
Triassic (1) sedimentary rocks in Salt southeastern Utah (Early Triassic)
Triassic (1) sedimentary rocks in Salt southwestern Utah (Early Triassic)
Triassic (1) sedimentary rocks in Salt Uinta Mountains-Uinta Basin region (Early Triassic)
Triassic (2) sedimentary rocks in central Utah (Middle to Late Triassic)
Triassic (2) sedimentary rocks in southeastern Utah (Late Triassic)
Triassic (2) sedimentary rocks in southwestern Utah (Late Triassic)
Triassic and Jurassic sedimentary rocks in southeastern Utah (Early Jurassic)
Triassic and Jurassic sedimentary rocks in southwestern Utah (Early to Middle Jurassic)
Upper Cambrian carbonate rocks in Logan-Huntsville Allochthon (Middle Cambrian to Early Ordovician)
Younger Precambrian metamorphic rocks in Uinta Mountains-Uinta Basin region (Proterozoic Y)

Virginia

Candler Formation - Lmestone (Cambrian)
Candler Formation - Limestone.
Juniata, Oswego, Martinsburg (Reedsville and Dolly Ridge), and Eggleston Formations (Ordovician)
Juniata, Oswego, Martinsburg (Reedsville and Dolly Ridge), and Eggleston Formations - Dusky-red shale and mudstone and sandstone; graywacke; shale and sandstone; and limestone.
Juniata, Reedsville, Trenton, and Eggleston Formations (Ordovician)
Juniata, Reedsville, Trenton, and Eggleston Formations - Dusky-red shale and mudstone and sandstone; shale and limestone. Note: one area in southeastern Bland County has landslides with intact stratigraphic units.
Lower Devonian, Silurian and Upper Ordovician Formations Undivided (Ordovician-Devonian)
Lower Devonian, Silurian and Upper Ordovician Formations Undivided - Some landslides with intact stratigraphic units in Giles County. Includes: Skrt, Sm, Oun, Ous, Ou, Om. (Shrc, Okpl?)
Lynchburg Group; Monumental Mills Formation (Proterozoic Z)
Lynchburg Group; Monumental Mills Formation - Metasandstone, laminated metasiltstone, and mudstone.
Maccrady Shale (Mississippian)
Maccrady Shale - Dusky-red and green shale and mudstone; and evaporite deposits.
Maccrady Shale and Price Formation (Mississippian)
Maccrady Shale and Price Formation - Includes: Maccrady Shale: Dusky-red and green shale and mudstone; and evaporite deposits. Price Formation: Sandstone, conglomeratic sandstone, and shale with carbonaceous partings and impure coal beds.
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
Moccasin or Bays Formation through Blackford Formation (Ordovician)
Moccasin or Bays Formation through Blackford Formation - Dusky-red shale and mudstone; sandstone; limestone, in part cherty; and calcareous shale.
Pennington Group (Mississippian)
Pennington Group - Shale, sandstone, dusky-red mudstone, conglomerate, siltstone, and limestone.
Silurian and Upper Ordovician Formations Undivided (Ordovician-Silurian)
Silurian and Upper Ordovician Formations Undivided - Includes: Skrt, Sm, Oun, Ous, Ou, Om. (Shrc and Okpl?)
Upper and Middle Ordovician Formations Undivided (Ordovician)
Upper and Middle Ordovician Formations Undivided - Includes: Oun, Ous, Ou, Om, Okpl, Oeln, Oml, Ols.

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.
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.
Pliocene nonmarine rocks (Pliocene)
Conglomerate, sandstone, shale, and mudstone. Tuffaceous in part; contains alluvial fan type material locally.
Pre-Tertiary sedimentary and metasedimentary rocks, undivided (Mostly Early Cretaceous to Middle Jurassic, possibly includes minor Eocene rocks)
Graywacke, argillite, phyllite, chert, talc, and graphite schist; some faulted-in blocks of serpentinite and greenstone. Includes minor limestone on San Juan Island.
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.
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 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.

Wisconsin

West Virginia

Wyoming

Aspen Shale (Phanerozoic | Mesozoic | Cretaceous-Early)
ASPEN SHALE--Light- to dark-gray siliceous tuffaceous shale and siltstone, thin bentonite beds, and quartzitic sandstone.
Chugwater and Dinwoody Formations (Phanerozoic | Mesozoic | Triassic-Early Triassic-Middle(?) Triassic-Late)
CHUGWATER AND DINWOODY FORMATIONS. CHUGWATER FORMATION--Red siltstone and shale. Alcova Limestone Member in upper middle part. Thin gypsum partings near base. DINWOODY FORMATION--Olive-drab hard dolomitic thin-bedded siltstone.
Cody Shale and Frontier Formation (N, S) (Phanerozoic | Mesozoic | Cretaceous-Late (78-83 Ma))
CODY SHALE AND FRONTIER FORMATION north and south Wyoming. CODY SHALE (AGE 78 TO 83 Ma) (Kc2)--Dull-gray shale, gray siltstone, and fine-grained gray sandstone. FRONTIER FORMATION (Kf2)--Gray sandstone and sandy shale.
Everts Formation, Eagle Sandstone, and Telegraph Creek Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
EVERTS FORMATION, EAGLE SANDSTONE, AND TELEGRAPH CREEK FORMATION--Massive to thin-bedded sandstone, mudstone, and shale.
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.
Goose Egg Formation (Phanerozoic | Paleozoic Mesozoic | Permian Triassic-Early)
GOOSE EGG FORMATION--Red sandstone and siltstone, white gypsum, halite, and purple to white dolomite and limestone.
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.
Hillard Shale (Phanerozoic | Mesozoic | Cretaceous-Late)
HILLIARD SHALE--Dark-gray to tan claystone, siltstone, and sandy shale.
Madison Group and Darby Formation (TB, N) or Madison Group and Three Forks and Jefferson Formations (Y) (Phanerozoic | Paleozoic | Devonian-Late Carboniferous Mississippian-Early(?) Mississippian-Middle(?) Mississippian-Late)
MADISON GROUP AND DARBY FORMATION (Thrust Belt, north Wyoming). MADISON GROUP--Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). DARBY FORMATION--Yellow and greenish-gray shale and dolomitic siltstone underlain by fetid brown dolomite and limestone. MADISON GROUP AND THREE FORKS AND JEFFERSON FORMATIONS (Yellowstone). MADISON GROUP--Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). THREE FORKS FORMATION--Pink, yellow, and green dolomitic siltstone and shale. JEFFERSON FORMATION--Massive siliceous dolomite.
Madison Limestone, Darby or Three Forks, Jefferson, and Beartooth Butte Formations, and Bighorn Dolomite (Phanerozoic | Paleozoic | Ordovician-Middle Ordovician-Late(?) Silurian(?) Devonian(?) Carboniferous Mississippian-Early(?) Mississippian-Middle(?) Mississippian-Late)
MADISON LIMESTONE, DARBY or THREE FORKS, JEFFERSON, AND BEARTOOTH BUTTE FORMATION. MADISON GROUP--Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). DARBY FORMATION--Yellow and greenish-gray shale and dolomitic siltstone underlain by fetid brown dolomite and limestone. THREE FORKS FORMATION--Yellow and greenish-gray shale and dolomitic siltstone. JEFFERSON FORMATION--Fetid brown dolomite and limestone. BEARTOOTH BUTTE FORMATION--Red sandstone, limy siltstone, and limestone. Occurs only in the Beartooth Mountains.
Mesaverde Group, Rock Springs Formation (Phanerozoic | Mesozoic | Cretaceous-Late)
MESAVERDE GROUP (SOUTH WYOMING). Rock Springs uplift. Rock Springs Formation--White to brown sandstone, shale, and claystone; numerous coal beds.
Sage Junction, Quealy, Cokeville, THomas Fork, and Smiths Formations (Phanerozoic | Mesozoic | Cretaceous-Early)
SAGE JUNCTION, QUEALY, COKEVILLE, THOMAS FORK, AND SMITHS FORMATIONS. SAGE JUNCTION FORMATION--Gray and tan siltstone and sandstone. QUEALY FORMATION--Variegated mudstone and tan sandstone. COKEVILLE FORMATION--Tan sandstone, claystone, limestone, bentonite, and coal. THOMAS FORK FORMATION--Variegated mudstone and gray sandstone. SMITHS FORMATION--Ferruginous black shale and tan to brown sandstone.
Spearfish Formation (Phanerozoic | Paleozoic Mesozoic | Permian Triassic-Early(?) Triassic-Middle(?) Triassic-Late)
SPEARFISH FORMATION--Red shale, red siltstone, and white gypsum beds; gypsum beds especially abundant near base.
Three Forks and Jefferson Formations and Bighorn Dolomite (Y) or Three Forks, Jefferson, and Beartooth Butte Formations and Bighorn Dolomite (N) (Phanerozoic | Paleozoic | Ordovician-Middle Ordovician-Late(?) Silurian(?) Devonian-Early(?) Devonian-Middle(?) Devonian-Late)
THREE FORKS, JEFFERSON, AND BEARTOOTH BUTTE FORMATIONS AND BIGHORN DOLOMITE (Yellowstone). THREE FORKS FORMATION--Pink, yellow, and green dolomitic siltstone and shale. JEFFERSON FORMATION--Massive siliceous dolomite. BEARTOOTH BUTTE FORMATION--Red sandstone, limy siltstone, and limestone. Occurs only in the Beartooth Mountains. BIGHORN DOLOMITE--Light-gray massive siliceous dolomite. THREE FORKS, JEFFERSON, AND BEARTOOTH BUTTE FORMATIONS AND BIGHORN DOLOMITE (north Wyoming). THREE FORKS FORMATION--Yellow and greenish-gray shale and dolomitic siltstone. JEFFERSON FORMATION--Fetid brown dolomite and limestone. BEARTOOTH BUTTE FORMATION--Red sandstone, limy siltstone, and limestone. Occurs only in the Beartooth Mountains. BIGHORN DOLOMITE--Gray massive cliff-forming siliceous dolomite and locally dolomitic limestone.
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 (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.
Wayan and Smiths Formations (Phanerozoic | Mesozoic | Cretaceous-Early)
WAYAN AND SMITHS FORMATIONS. WAYAN FORMATION--Variegated mudstone, siltstone, and sandstone. SMITHS FORMATION--Ferruginous black shale and tan to brown sandstone.