Geologic units containing mud

Mineral Resources On-Line Spatial Data

Clay or mud

A loose, earthy, extremely fine-grained, natural sediment composed primarily of clay-size or colloidal particles and characterized by high plasticity and by a considerable content of clay minerals...

This category is also used for Clay, mud and mud.

Subtopics:
(none)

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).
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.
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 northeastern AL and part of the Sequatchie anticline. 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 eastern part of Interior Low Plateaus province and 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.
Selma Group; Blufftown Formation (Cretaceous): Blufftown Formation - (Selma Group), The Blufftown extends from the Chattahoochee River Valley westward into central Russell County where it is divided into two westward-extending tongues by an eastward-extending tongue of the Mooreville Chalk. In the Chattahoochee River Valley the Blufftown is mainly glauconitic calcareous fine sand, micaceous clay and marl, fossiliferous clay, gray calcareous fossiliferous sandstone, and carbonaceous clay and silt. To the west the lower tongue of the Blufftown is gravelly sand, glauconitic sand, calcareous clay, and sandy clay and merges with the lower part of the Mooreville Chalk in southwestern Macon County. The upper tongue is mainly calcareous sandy clay and micaceous silty fine sand with thin layers of limestone and sandstone. The upper tongue merges with the Mooreville Chalk and the lower part of the Demopolis Chalk in western Bullock County.
Selma Group; Mooreville Chalk (Cretaceous): Mooreville Chalk - (Selma Group), Yellowish-gray to olive-gray compact fossiliferous clayey chalk and chalky marl. The unconformable contact at the base is characterized by a bed of glauconitic, chalky sand containing phosphate pellets and molds of fossils. The Arcola Limestone Member at the top consists of two to four beds of light-gray brittle, dense, fossiliferous limestone separated by beds of light-gray to pale-olive calcareous clay.
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.
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

Nacatoch Sand (Phanerozoic | Mesozoic | Cretaceous-Late): Nacatoch Sand
Silt and sand (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Early): Silt and sand - Contains lenses of gravel and clay
Wilcox Group (Phanerozoic | Cenozoic | Tertiary | Eocene-Early): Wilcox Group
Woodbine Formation (Phanerozoic | Mesozoic | Cretaceous-Late): Woodbine Formation

Arizona

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 Pleistocene to late Miocene basin deposits (Late Pliocene to Early Pleistocene): Poorly sorted, variably consolidated gravel and sand that range widely in age. These sediments are generally light gray or tan. This unit is generally mapped in areas of deep late Cenozoic stream incision and landscape degradation where thin Quaternary deposits (map units Qy, Qm, Qo) discontinuously blanket older deposits (map units Tsy or Tsm) and the two cannot be differentiated at the scale of this map. (0.75-10 Ma)
Early Pleistocene to latest Pliocene surficial deposits (Late Pliocene to Early Pleistocene): Coarse relict alluvial fan deposits that form rounded ridges or flat, isolated surfaces that are moderately to deeply incised by streams. These deposits are generally topographically high and have undergone substantial erosion. Deposits are moderately to strongly consolidated, and commonly contain coarser grained sediment than younger deposits in the same area. (0.75-3 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)
Holocene river alluvium (Holocene): Unconsolidated to weakly consolidated sand and gravel in river channels and sand, silt, and clay on floodplains. Also includes young terrace deposits fringing floodplains. (0-10 ka)
Holocene surficial deposits (Holocene): Unconsolidated deposits associated with modern fluvial systems. This unit consists primarily of fine-grained, well-sorted sediment on alluvial plains, but also includes gravelly channel, terrace, and alluvial fan deposits on middle and upper piedmonts. (0-10 ka)
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)
Late and middle Pleistocene surficial deposits (Middle to Late Pleistocene): Unconsolidated to weakly consolidated alluvial fan, terrace, and basin-floor deposits with moderate to strong soil development. Fan and terrace deposits are primarily poorly sorted, moderately bedded gravel and sand, and basin-floor deposits are primarily sand, silt, and clay. (10-750 ka)
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)
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)
Quaternary surficial deposits, undivided (Quaternary): Unconsolidated to strongly consolidated alluvial and eolian deposits. This unit includes: coarse, poorly sorted alluvial fan and terrace deposits on middle and upper piedmonts and along large drainages; sand, silt and clay on alluvial plains and playas; and wind-blown sand deposits. (0-2 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
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 3 (Mescal Range) (Middle Jurassic to late Early Cretaceous): Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges
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 (?) (Cretaceous (?)): Lower Cretaceous sandstone, shale, and conglomerate (?)
Miocene marine rocks and Franciscan schist (Cretaceous(?) to Miocene)
Miocene nonmarine rocks (Oligocene to Pleistocene): Sandstone, shale, conglomerate, and fanglomerate; in part Pliocene and Oligocene.
Oligocene nonmarine rocks, unit 1 (Northern California) (Oligocene to Miocene): Sandstone, shale, and conglomerate; in part Miocene and Eocene.
Oligocene nonmarine rocks, unit 2 (Central and Southern California) (middle Eocene to early Miocene): Sandstone, shale, and conglomerate; in part Miocene and Eocene.
Paleozoic marine rocks, undivided, unit 4 (Western Sierra Nevada) (Ordovician to Triassic): Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite
Paleozoic marine rocks, undivided, unit 9 (Western Klamath Mountains) (Devonian to Jurassic): Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite
Paleozoic metavolcanic rocks, unit 1 (Eastern Klamath Mountains) (Devonian and Permian): Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks
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
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.
Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 1 (Cascade Volcanic Field) (Holocene): Recent (Holocene) pyroclastic and volcanic mudflow deposits; in part Pleistocene.
Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 2 (Mono Craters) (Holocene): Recent (Holocene) pyroclastic and volcanic mudflow deposits; in part Pleistocene.
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 nonmarine rocks, undivided (Paleocene to Pliocene): Undivided Tertiary sandstone, shale, conglomerate, breccia, and ancient lake deposits.
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

Colorado

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)
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

Delaware

Bryn Mawr Formation (?): Bryn Mawr Formation - Red and brown quartz sand with silt, clay and fine gravel.
Columbia Formation (Pleistocene): Columbia Formation - Yellow and reddish brown quartz sand with gravel and little clay

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).
Citronelle Formation (Pliocene): Citronelle Formation - The Citronelle Formation is widespread in the Gulf Coastal Plain. The type section for the Citronelle Formation, named by Matson (1916), is near Citronelle, Alabama. The Citronelle Formation grades laterally, through a broad facies transition, into the Miccosukee Formation of the eastern Florida panhandle. Coe (1979) investigated the Citronelle Formation in portions of the western Florida panhandle. The Citronelle Formation is a siliciclastic, deltaic deposit that is lithologically similar to, and time equivalent with, the Cypresshead Formation and, at least in part, the Long Key Formation (Cunningham et al., 1998) of the peninsula. In the western panhandle, some of the sediments mapped as Citronelle Formation may be reworked Citronelle. The lithologies are the same and there are few fossils present to document a possible younger age. The Citronelle Formation consists of gray to orange, often mottled, unconsolidated to poorly consolidated, very fine to very coarse, poorly sorted, clean to clayey sands. It contains significant amounts of clay, silt and gravel which may occur as beds and lenses and may vary considerably over short distances. Limonite nodules and limonite-cemented beds are common. Marine fossils are rare but fossil pollen, plant remains and occasional vertebrates are found. Much of the Citronelle Formation is highly permeable. It forms the Sand and Gravel Aquifer of the surficial aquifer system.
Hawthorn Group, Arcadia Formation (Oligocene/Miocene): Hawthorn Group, Arcadia Formation - The undifferentiated Arcadia Formation and the Tampa Member crop out on the southwestern flank of the Ocala Platform from Pasco County southward to Sarasota County. Although ages of the outcropping sediments have not been accurately determined, stratigraphic position suggests that the Upper Oligocene parts of the Arcadia Formation and Tampa Member are exposed in this region, particularly from Hillsborough County northward to Pasco County. The Arcadia Formation, named by Scott (1988), is predominantly a carbonate unit with a variable siliciclastic component, including thin beds of siliciclastics. Within the outcrop area, the Arcadia Formation, with the exception of the Tampa Member, is composed of yellowish gray to light olive gray to light brown, micro to finely crystalline, variably sandy, clayey, and phosphatic, fossiliferous limestones and dolostones. Thin beds of sand and clay are common. The sands are yellowish gray, very fine to medium grained, poorly to moderately indurated, clayey, dolomitic and phosphatic. The clays are yellowish gray to light olive gray, poorly to moderately indurated, sandy, silty, phosphatic and dolomitic. Molds and casts of mollusks are common in the dolostones. Silicified carbonates and opalized claystone are found in the Arcadia Formation.
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, Torreya Formation (Miocene): Hawthorn Group, Torreya Formation - Torreya Formation - The Torreya Formation is exposed or near the surface from western Gadsden County eastward to western-most Hamilton County. It is informally subdivided into a lower carbonate unit and an upper siliciclastic unit (Scott, 1988). The majority of Torreya Formation outcrops expose the siliciclastic part of the unit. The carbonate sediments are white to light olive gray, generally poorly indurated, variably sandy and clayey, fossiliferous (molds and casts) limestone (mudstone and wackestone). The limestones often grade into calcareous-cemented sands. Phosphate is present in the carbonate sediments, particularly in the Sopchoppy Member. The siliciclastics vary from white to light olive gray, unconsolidated to poorly indurated, slightly clayey sands with minor phosphate to light gray to bluish gray, poorly consolidated, variably silty clay (Dogtown Member). The siliciclastics are sporadically fossiliferous. The Torreya Formation overlies the FAS and forms part of the intermediate confining unit/aquifer system.
Residuum on Oligocene sediments (Oligocene): Residuum on Oligocene sediments - The undifferentiated Oligocene residuum, mapped on parts of the Chattahoochee "Anticline", characteristically consists of reddish brown, variably sandy clay with inclusions of variably fossiliferous, silicified limestone (Huddlestun, 1993). The residuum includes Lower and Upper Oligocene weathered sediments (Huddlestun, 1993).
Reworked Cypresshead sediments (Pliocene/Pleistocene): Reworked Cypresshead sediments - Undifferentiated reworked Cypresshead Formation- This unit is the result of post depositional reworking of the Cypresshead siliciclastics. The sediments are fine to coarse quartz sands with scattered quartz gravel and varying percentages of clay matrix.
Shelly sediments of Plio-Pleistocene age (Pliocene/Pleistocene): Shelly sediments of Plio-Pleistocene age - Tertiary-Quaternary Fossiliferous Sediments of Southern Florida - Molluskbearing sediments of southern Florida contain some of the most abundant and diverse fossil faunas in the world. The origin of these accumulations of fossil mollusks is imprecisely known (Allmon, 1992). The shell beds have attracted much attention due to the abundance and preservation of the fossils but the biostratigraphy and lithostratigraphy of the units has not been well defined (Scott, 1992). Scott and Wingard (1995) discussed the problems associated with biostratigraphy and lithostratigraphy of the Plio-Pleistocene in southern Florida. These "formations" are biostratigraphic units. The "formations" previously recognized within the latest Tertiary-Quaternary section of southern Florida include the latest Pliocene - early Pleistocene Caloosahatchee Formation, the early Pleistocene Bermont formation (informal) and the late Pleistocene Fort Thompson Formation. This section consists of fossiliferous sands and carbonates. The identification of these units is problematic unless the significant molluscan species are recognized. Often exposures are not extensive enough to facilitate the collection of representative faunal samples to properly discern the biostratigraphic identification of the formation. In an attempt to alleviate the inherent problems in the biostratigraphic recognition of lithostratigraphic units, Scott (1992) suggested grouping the latest Pliocene through late Pleistocene Caloosahatchee, Bermont and Fort Thompson Formations in to a single lithostratigraphic entity, the Okeechobee formation (informal). In mapping the shelly sands and carbonates, a generalized grouping as Tertiary-Quaternary shell units (TQsu) was utilized. This is equivalent to the informal Okeechobee formation. The distribution of the Caloosahatchee and Fort Thompson Formation are shown on previous geologic maps by Cooke (1945), Vernon and Puri (1964) and Brooks (1982). The Nashua Formation occurs within the Pliocene - Pleistocene in northern Florida. However, it crops out or is near the surface is an area too small to be shown on a map of this scale. Lithologically these sediments are complex, varying from unconsolidated, variably calcareous and fossiliferous quartz sands to well indurated, sandy, fossiliferous limestones (both marine and freshwater). Clayey sands and sandy clays are present. These sediments form part of the surficial aquifer system

Georgia

Clayton Formation (Paleocene): Clayton Formation
Tallahatta Formation (Eocene): Tallahatta Formation

Iowa

Ft. Dodge Beds (Phanerozoic | Mesozoic | Jurassic): Gypsum and red and green shale; in Webster CO only

Idaho

Basalt, clay, and gravel; Late Pleistocene basalt flows with interlayered alluvial and lacustrine sediments; Snake River Plain and vicinity (subunits are Qpu1b, Qpu2b, Qpu3b, and Qpu4b) (Late Pleistocene): Upper Pleistocene Snake Plain lava flows; local stratigraphic position shown by (Qpu4b, Qpu3b, Qpu2b, Qpu1b).
Basalt, clay, and pumice; Late Pleistocene basalt flows, volcaniclastic debris, and ponded sediments of subunit 4b; Snake River Plain; (Late Pleistocene): Upper Pleistocene Snake Plain basaltic lava flows, unit 4.
Gravel; Early Pleistocene alluvium; western Snake River Plain (Pleistocene): Lower Pleistocene deposits; outwash, fanglomerate, flood and terrace gravels.
Gravel, sand, and clay; Quaternary-Tertiary colluvium and fanglomerate; western Idaho (Pleistocene and Pliocene): Pleistocene and Pliocene fanglomerate, colluvium, and poorly sorted gravel deposits.
Gravel, sand, silt, clay; Late Pleistocene glacio-alluvial and lacustrine deposits; Basin and Range, and Snake River Plain (Late Pleistocene): Upper Pleistocene deposits; outwash, fanglomerate, flood and terrace gravels.
Silt, clay, and diatomite; Middle Pleistocene lacustrine sediments of lava-dammed lakes; western Snake River Plain (Middle Pleistocene): Middle Pleistocene lava-dammed Snake Plain lake beds of silt, clay and diatomite.

Illinois

Abbott Formation (Pennsylvanian): Abbott Formation
Bond Formation (Pennsylvanian): Bond Formation
Carbondale Formation (Pennsylvanian): Carbondale Formation
Modesto Formation (Pennsylvanian): Modesto Formation
Spoon Formation (Pennsylvanian): Spoon (includes Pa in northeast)

Indiana

Carbondale Group (Pennsylvanian): Carbondale Group - Mostly shale and sandstone; also includes thin beds of limestone, clay, and coal. S, Springfield Coal Member
Raccoon Creek Group (Pennsylvanian): Raccoon Creek Group - Mostly shale and sandstone; also includes thin beds of limestone, clay, and coal. B, Buffaloville Coal Member; LB, Lower Block Coal Member
Whitewater Formation (Ordovician): Whitewater Formation - Skeletal limestone and calcareous shale; dolomitic mudstone (S, Saluda Member) at base

Kansas

Alluvium (Phanerozoic | Cenozoic | Quaternary | Pleistocene): unconsolidated sand, silt, clay, and gravel
Alluvium (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene): unconsolidated sand, silt, clay, and gravel
Drift (Phanerozoic | Cenozoic | Quaternary | Pleistocene): sand, silt, clay, and some gravel

Louisiana

Carnahan Bayou Member (Phanerozoic | Cenozoic | Tertiary | Miocene): yellow to gray siltstones, sandstones, and clays with thin tuffaceous beds; some lenses of black chert gravel; petrified wood locally.
Williamson Creek Member (Phanerozoic | Cenozoic | Tertiary | Miocene): white to gray silts, siltstones, silty clays, and sand beds; some lenses of black chert gravel.

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).
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).
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).
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).
Tertiary sediments (Tertiary): Tertiary sediments - Unconsolidated sand, silt, and clay in discontinuous patches; contains Tertiary fossils; may include Pleistocene sediments (cross section only).

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.
Lowland Deposits (Quaternary): Lowland Deposits - Gravel, sand, silt, and clay. Medium- to coarse-grained sand and gravel; cobbles and boulders near base; commonly contains reworked Eocene glauconite; varicolored silts and clays; brown to dark gray lignitic silty clay; contains estuarine to marine fauna in some areas (includes in part Pamlico, Talbot, Wicomico and Sunderland Formations of earlier reports); thickness 0 to 150 feet.
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.
Potomac Group, including Raritan and Patapsco Formations, Arundel Clay, and Patuxent Formation (Cretaceous): Potomac Group - Interbedded quartzose gravels; protoquartzitic to orthoquartzitic argillaceous sands; and white, dark gray, and multicolored silts and clays; thickness 0 to 800 feet. Includes Raritan and Patapsco Formations - Gray, brown, and red variegated silts and clays; lenticular, cross-bedded, argillaceous, subrounded sands; minor gravels; thickness 0 to 400 feet; Arundel Clay - Dark gray and maroon lignitic clays; abundant siderite concretions; present only in Baltimore-Washington area; thickness 0 to 100 feet; and Patuxent Formation - White or light gray to orange-brown, moderately sorted, cross-bedded, argillaceous, angular sands and subrounded quartz gravels; silts and clays subordinate, predominantly pale gray; thickness 0 to 250 feet.
Quaternary Deposits Undivided (Quaternary): Quaternary Deposits Undivided - Undifferentiated gray to buff sand and gravel, gray to brown lignitic silt and clay, occasional boulders, and rare shell beds. Surficial deposits occur as intercalated fluvial sands and marsh muds (e.g. in upstream floodplain of the Wicomico and Nanticoke Rivers), well-sorted, stablized dune sands (e.g. eastern Wicomico County), shell-bearing estuarine clays and silts (e.g. lower Dorchester County) and Pocomoke River basin of Worcester County), and beach zone sands (e.g. Fenwick and Assateague Islands). Wisconsin to Holocene in age. Subsurface deposits of pre-Wisconsin age consist of buff to reddish-brown sand and gravel locally incised into Miocene sediments (e.g. Salisbury area), estuarine to marine white to gray sands, and gray to blue, shell-bearing clays (e.g. Worcester County).
Upland Deposits (Eastern Shore) (Quaternary): Upland Deposits (Eastern Shore) - Gravel, sand, silt, and clay. Mostly cross-bedded, poorly sorted, medium- to coarse-grained white to red sand and gravel; boulders near base; minor pink and yellow silts and clays; (Wicomico Formation of earlier reports); thickness 0 to 90 feet, locally thicker in paleochannels.
Upland Deposits (Western Shore) (Quaternary): Upland Deposits (Western Shore) - Gravel and sand, commonly orange-brown, locally limonite-cemented; minor silt and red, white, or gray clay; (includes Brandywine, Bryn Mawr, and Sunderland Formations of earlier reports); lower gravel member and upper loam member in Southern Maryland; thickness 0 to 50 feet.

Maine

Devonian Beck Pond Limestone (Devonian): Devonian Beck Pond Limestone
Ordovician Benner Hill formation (Ordovician): Ordovician Benner Hill formation
Precambrian Z North Haven Formation (Precambrian): Precambrian Z North Haven Formation

Michigan

Portage Lake Volcanics (Middle Proterozoic): Portage Lake Volcanics - Lava flows, mostly basalt, andesite and felsite flows and subordinate interflow sedimentary rocks.

Missouri

CHEROKEE GROUP- Cabaniss Subgroup, Krebs Subgroup (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Middle Desmonian]): CHEROKEE GROUP - Cabaniss Subgroup - cyclic deposits, shale, sandstone, clay and several workable coal beds. Krebs Subgroup - cyclic deposits, sandstone, siltstone, shale, clay and some workable coal beds
MARMATON GROUP (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Middle Desmonian]): MARMATON GROUP - cyclic deposits, shale and limestone with sandstone, clay and several coal beds, some workable
PLEISTOCENE SERIES (Phanerozoic | Cenozoic | Quaternary | Pleistocene): PLEISTOCENE SERIES - Loess, till, drift, clay, silt, sand and gravel (shown on cross section, not on map)
RIVERTON FORMATION, BURGNER FORMATION (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Atokan]): RIVERTON FORMATION - shale, clay, coal. BURGNER FORMATION - limestone

Mississippi

Catahoula formation (Miocene): Catahoula formation - Irregularly bedded gray sand and sandstone; mottled red and gray, green, and chocolate-colored clay; some quartzite, and some gravel; the Paynes Hammock sand, sandy limestone cross-bedded fine green sand, and thin-bedded sand and clay, is mapped with the underlying Chickasawhay limestone in eastern MS.
Citronelle formation (Pleistocene): Citronelle formation - Red sand and gravel and white clay; may be of Pliocene age; the formation mapped is equivalent to the Willis sand and does not include the terrace deposits, colluvium, and residuum commonly considered "Citronelle".
Clayton formation (Paleocene): Clayton formation - (Midway group), Upper part, greenish-gray coarsely glauconitic sandy clay and marl; lower part, crystalline sandy limestone and loose sand, represented south of Houston by a discontinuous bed of indurated calcareous sandstone.
Coastal deposits (Holocene): Coastal deposits - Loam, sand, gravel and clay.
Vicksburg group and Chickasawhay limestone (Oligocene): Vicksburg group and Chickasawhay limestone - Chickasawhay limestone, sandy limestone, and sand, present only in eastern MS (mapped with it is the overlying Paynes Hammock sand of Miocene age); Vicksburg group, predominantly limestone and marl, but contains some bentonite and near the top, chocolate-colored clay and some sand.

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.
Belgrade Formation, Undivided (Tertiary): Belgrade Formation, Undivided - Pollocksville Member: oyster-shell mounds in tan to orange sand matrix, indurated locally. Haywood Landing Member: fossiliferous clayey sand, gray to brown. Members grade into each other laterally.
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; Sanford Formation (Triassic): Sanford Formation - conglomerate, fanglomerate, sandstone, and mudstone.
Newark Supergroup, Dan River Group; Dan River Group, Undivided (Triassic): Dan River Group, Undivided - basin-margin conglomerate and sandstone, red to brown, interfingering with basin-center sandstone and mudstone, green to brown. Conglomerate shown by pattern.
Newark Supergroup, Dan River Group; Stoneville Formation (Triassic): Stoneville Formation - conglomerate, sandstone, and mudstone, lenticular and laterally-gradational bedding.
Surficial Deposits, Undivided (Quaternary): Surficial Deposits, Undivided - sand, clay, gravel, and peat deposited in marine, fluvial, eolian, and lacustrine environments. Quaternary deposits not shown at altitudes greater than approx. 205 feet above mean sea level (Suffolk Scarp, in part).
Terrace Deposits and Upland Sediment (Tertiary): Terrace Deposits and Upland Sediment - gravel, clayey sand, and sand, minor iron-oxide cemented sandstone.
Waccamaw Formation (Tertiary): Waccamaw Formation - fossiliferous sand with silt and clay, bluish-gray to tan, loosely consolidated. Straddles Pleistocene-Pliocene boundary.

North Dakota

Bullion Creek Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene): Yellow-brown silt, sand, clay, sandstone, and lignite; river, lake, and swamp sediment; as thick as 200 meters (600 feet).
Hell Creek Formation (Phanerozoic | Mesozoic | Cretaceous-Late): Gray sand, silt, clay, and sandstone; river sediment; as thick as 150 meters (500 feet).
Ludlow Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene): Gray-brown and yellow-brown silt, sand, clay and sandstone, and lignite; river, lake, and swamp sediment; as thick as 100 meters (300 feet).
Sentinel Butte Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene): Gray-brown silt, sand, clay, sandstone, and lignite; river, lake, and swamp sediment; as thick as 200 meters (600 feet).
Slope Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene): Gray-brown and yellow-brown silt, sand, clay, sandstone, and lignite; river, lake, and swamp sediment; as thick as 100 meters (300 feet).

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).
Cohansey Formation (Middle Miocene, Serravallian): Cohansey Formation - Sand, white to yellow with local gravel and clay. Locally stained red or orange brown by iron oxides and (or) cemented into large blocks of ironstone. Unweathered clay is typically dark gray, but commonly weathers white where interbedded with thin beds of ironstone. Unit is a complex of interfingering marine and nonmarine facies. Sand is typically medium grained and moderately sorted although it ranges from fine to very coarse grained and from poorly to well sorted. Sand consists of quartz and siliceous rock fragments. Some beds are locally micaceous, and in the Lakehurst area, Ocean County, some beds have high concentrations of "black" sand (pseudorutile) that was once extensively mined. In general, the sand is crossbedded, although the style of crossbedding varies significantly with the paleoenvironment. Trough crossbedding predominates, especially in the nonmarine channel fill deposits, and the scale of the crossbeds varies from small to large. In some areas, planar bedding is well developed in sections that have abundant marine burrows (mostly the clay-lined trace fossil Ophiomorpha nodosa). Such marine-influenced beds (largely foreshore deposits) occur on the central sheet west of Asbury Park, near Adelphia, Monmouth County, north of the Lakehurst Naval Air Station, Ocean County, and at Juliustown, Burlington County (Owens and Sohl, 1969), and on the southern sheet as far north as Salem, Salem County. Gravel beds occur locally, especially in updip areas such as near New Egypt, Ocean County, in the Atlantic Highlands and in the highlands west of Barnegat, Ocean County, in the southern part of the central sheet and in mixed marine and nonmarine facies in the northeastern part of the southern sheet where gravel occurs in well-defined channels. Most of the gravel is 1.3 to 2.5 cm (0.5-1.0 in) in diameter, but pieces as long as 10 cm (4 in) are present. The gravel is composed of quartz with small amounts of black chert and quartzite. Clay commonly occurs as discrete, thin, discontinuous beds, is dark gray where unweathered, white or red where weathered. Lesser, thin laminated clay strata also are present. Locally, as near Lakehurst, thick, dark-gray, very lignitic clay was uncovered during the mining of ilmenite and is informally called the Legler lignite (Rachele, 1976). An extensive, well-preserved leaf flora was collected from a thick clay lens in a pit near Millville, Cumberland County. The leaf flora was dominated by Alangium sp., a tree no longer growing in eastern North America (J.A. Wolfe, written commun., 1992). Maximum thickness in the map area is about 60 m (197 ft); however, thickness is difficult to determine because of the irregular basal contact and extensive post-depositional erosion. There is as much as 18 m (59 ft) of relief along the basal contact. The basal contact is sharp, undulatory, and directly overlain by a thin gravel bed. The Cohansey Formation unconformably overlies the Kirkwood Formation and is found in channels cut down into the Kirkwood. Where the Kirkwood consists of sandy, light-colored sediments, the basal contact of the Cohansey is drawn below crossbedded sediments. Where the Kirkwood consists of dark-colored silty beds, the basal contact is drawn between light-colored Cohansey sediments and the underlying dark-colored sediments. The Cohansey was markedly thinned because of erosion prior to deposition of overlying units in the western and southern parts of the southern sheet (Owens and Minard, 1975). The unit has been extensively eroded and stripped from large areas of the New Jersey Coastal Plain, particularly in the central sheet where outliers are common. In spite of its widespread nature, the Cohansey is poorly exposed because of its loose sandy composition, which causes it to erode easily (Newell and others, in press). Because of this same sandy nature, the Cohansey has been widely mined for sand, and manmade exposures are common in many areas. The age of the Cohansey is controversial because no calcareous microfauna or macrofauna have been found in this formation. The best indication of age comes from pollen and spores obtained from dark carbonaceous clay. Rachele (1976) analyzed the microflora from the Legler site and noted that the Cohansey had a rich and varied assemblage including several genera labeled "exotics" which no longer occur in the northeastern United States: Engelhardia, Pterocarya, Podocarpus, and Cyathea. Greller and Rachele (1984) estimated a middle Miocene age. Ager's (in Owens and others, 1988) analysis of the Cohansey from a corehole at Mays Landing also suggests a middle Miocene (Serravallian) age.
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).
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).
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.
Magothy Formation (Upper Cretaceous, middle and lower Santonian): Magothy Formation - Sand, quartz, fine- to coarse-grained, locally gravelly (especially at the base), white; weathers yellow brown or orange brown, interbedded with thin-bedded clay or dark-gray clay-silt mainly at the top of the formation. Muscovite and feldspar are minor sand constituents. Large wood fragments occur in many clay layers. Clay weathers to gray brown or white. Formation characterized by local vertical and lateral facies changes. The Magothy is best exposed and thickest (about 80 m (262 ft)) in the Raritan Bay area. The outcrop belt is widest in the north and narrows to the southwest. The formation is about 25 m (82 ft) thick or less in the southern sheet. The formation is poorly exposed because of its sandy nature and its widespread cover by younger sediments. The old geologic map of New Jersey (Lewis and Kummel, 1910-1912, revised 1950) showed the Magothy to consist of only one lithology (Cliffwood beds at Cliffwood Beach, Monmouth County). Subsequent pollen studies of the Magothy and the underlying Raritan Formation showed most of the Raritan to be the same age as the Magothy. Wolfe and Pakiser (1971) redefined and considerably expanded the Magothy. Kummel and Knapp (1904) had already recognized that the Magothy, as used here, contained a large number of lithologies. At the time of their study, the Magothy was extensively mined for clay and sand and was well exposed. Their subdivisions had economic designations (for example, Amboy stoneware clay). Barksdale and others (1943) later gave geographic names to these subdivisions, discussed individually below. The lower contact of the Magothy in the Delaware River valley is difficult to place because the lower part of the Magothy is lithically similar to the underlying Potomac Formation. The contact is placed at the base of the lowest dark-gray clay in the Magothy. The best faunas from the Magothy were obtained from siderite concretions and slabs in and near Cliffwood Beach representing only the top of the formation. These faunas were discussed in detail by Weller (1904, 1907) and supplemented by Sohl (in Owens and others, 1977). The presence of Ostrea cretacea in the Cliffwood Beach fauna suggests that the upper part of the Magothy is late Santonian in age. Wolfe and Pakiser (1971) and Christopher (1979, 1982) discussed the microfloral assemblage in the Magothy. Christopher subdivided the Magothy into three zones: Complexipollis exigua-Santalacites minor (oldest), ?Pseudoplicapollis longiannulata-Plicapollis incisa (middle), and ?Pseudoplicapollis cuneata-Semioculopollis verrucosa (youngest). The oldest zone, originally considered to be as old as Turonian, was subsequently considered to be post-Coniacian Christopher, 1982). The middle and upper zones are also probably Santonian. Christopher (1979) followed the nomenclature for the subdivisions elaborated upon earlier. The Cliffwood and Morgan beds, and, presumably the upper thin-bedded sequence, would include the youngest pollen zone; the Amboy Stoneware Clay Member and perhaps the uppermost part of the Old Bridge Sand Member, the middle pollen zone; and the lower part of the Old Bridge Sand Member and South Amboy Fire Clay Member, the oldest pollen zone. The Magothy is considered herein to be of Santonian age. Cliffwood beds - Typically very sandy, horizontally bedded to crossbedded, mainly small-scale trough crossbeds. Thin layers of dark, fine, carbonaceous matter are interbedded with sand. Carbonaceous units are conspicuously micaceous; the sand is less so. Sand is typically fine to medium grained and locally burrowed. Burrows include the small-diameter Ophiomorpha nodosa and some that are not clay lined. Slabs of dark-reddish-brown siderite were common at the base of the bluff at Cliffwood Beach before the outcrop was covered. Some of these slabs had many fossil molds, typically a large number of pelecypods. Lower in the section, between high and low tide level, there is a pale-gray clay-silt about 1.5 m (5 ft) thick with many small reddish-brown siderite concretions. These concretions have many fossils that were described in detail by Weller (1904). The Cliffwood beds are about 7.5 m (25 ft) thick in outcrop. Equivalents of the Cliffwood beds are exposed near the Delaware River between Trenton and Florence, Burlington County. These beds are mainly sand, as are those at Cliffwood Beach, but they tend to have more crossbedding than the typical Cliffwood strata and no burrows or marine fossils. In addition, beds of quartz gravel are present in the Cliffwood near Riverside, Burlington County. Morgan beds - Occur only in the northern part of the central sheet. They consist of interbedded, thin, dark-colored clay and fine-grained, light-colored, micaceous sand. Clay is locally more abundant in the Morgan than in the Cliffwood beds. Sand ranges from massive to locally crossbedded and locally has fine organic matter. This unit is exposed only in the South Amboy quadrangle where it is as much as 12 m (39 ft) thick. It grades downward into underlying clay. Amboy Stoneware Clay Member - Crops out only in the South Amboy quadrangle in the central sheet and is mainly dark-gray, white-weathering, interbedded clay and silt to fine-grained quartz sand. Clay has abundant, fine, carbonaceous matter and fine mica flakes. Small cylindrical burrows are abundant in this unit. Locally, the clay is interbedded with sand and contains large pieces of lignitized, bored (Teredolites) logs. Large slabs of pyrite-cemented sand are associated with the woody beds. Amber occurs in some of the wood. Unit is approximately 7.5 m (25 ft) thick, but pinches out along strike. The Amboy Stoneware is disconformable on the underlying sand. Old Bridge Sand Member - Predominantly a light-colored sand, extensively crossbedded and locally interbedded with dark-gray laminae; clay is highly carbonaceous, woody, in discontinuous beds, especially near the base. The scale of crossbedding varies from small to large. Locally, small burrows are present. Unit is as much as 12 m (39 ft) thick and rests disconformably on the underlying unit. South Amboy Fire Clay Member - Basal member of the Magothy Formation. Unit resembles the Amboy Stoneware Clay Member, particularly in its lensing character. Unit is best exposed in the central sheet in the South Amboy quadrangle and in the Delaware River valley at the base of the bluffs at Florence. The South Amboy is a dark, massive to finely laminated clay, locally oxidized to white or red. Unit fills large channels and has local concentrations of large, pyrite-encrusted, lignitized logs. Some of the clay is slumped, suggesting post-depositional undercutting during channel migration. The clay is interbedded with fine- to medium-grained, crossbedded sand. The basal contact with the underlying Raritan is well exposed in the Sayre and Fisher Pit in Sayreville, Middlesex County, where the contact is marked by a deeply weathered gravel zone.
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.
Raritan Formation (Upper Cretaceous, upper Cenomanian): Raritan Formation - Consists of an upper clayey silt (Woodbridge Clay Member) and a lower sand (Farrington Sand Member). Formation occurs only in northern part of central sheet. Woodbridge Clay Member - Silt, clayey, dark-gray; weathers to red brown or white, locally interbedded with light-gray, clayey, fine- to very fine grained sand (primarily quartz and mica with little feldspar). Very micaceous (muscovite, chlorite, and biotite) in both silty and sandy beds. Very woody, mostly fine pieces in layers and coated with pyrite. Locally, tree stumps, in upright position, are found near base of unit as are transported individual logs several feet in length. Siderite occurs in discontinuous beds and as flattened slab concretions as much as 0.6 m (2 ft) in maximum diameter. Fossil casts of marine mollusks are present, particularly near the top of the formation. Locally, well-developed burrows of Ophiomorpha nodosa filled with iron oxides weather out of the clay-silt. The Woodbridge is approximately 20 m (66 ft) thick in the vicinity of Sayreville, Middlesex County, where the South River has stripped away the overlying Magothy Formation, and it crops out in many places in the Perth Amboy and New Brunswick quadrangles to the north, but not in the quadrangles to the south or southwest. The Woodbridge does not crop out in the Delaware River valley southwest of Trenton. The late Cenomanian ammonites Metoicoceras bergquisti and Metengonoceras sp. were described from the upper part of the Woodbridge (Cobban and Kennedy, 1990). Pollen from the unit belongs to the Complexipollis-Atlantopollis Assemblage Zone of latest Cenomanian and early Turonian age (Christopher, 1979, 1982). Farrington Sand Member - Sand, quartz, fine- to medium-grained, crossbedded, very micaceous, white, interbedded with thin to thick, dark, silt beds. Rock fragments are a minor sand constituent. No burrows were observed in the unit. Unit is exposed only in pits dug below the overlying Woodbridge Clay Member. Typically, thickness is about 9 to 10.5 m (30-34 ft). Pollen from the Farrington is similar to the pollen in the Woodbridge.
Shark River Formation (upper and middle Eocene, Priabonian through Lutetian): Shark River Formation - Glauconite sand, silt, and clay, medium- to coarse-grained, light-brown to medium-gray, locally indurated at top and noncalcareous throughout. Mollusk impressions (mainly Venericardia perantiqua) were observed in the Farmingdale quadrangle. The Shark River is exposed only at a few localities in the central sheet near Farmingdale, Monmouth County, along the Manasquan and Shark Rivers and in several tributaries to Deal Lake near Asbury Park in the Asbury Park quadrangle (Sugarman and Owens, 1994). Most outcrops are small, less than 3 m (10 ft) in height. The contact with the underlying Manasquan Formation was not observed. The Shark River is about 18 m (59 ft) thick and consists of two fining-upward cycles: a glauconite sand is present at the base and a clay or silt is present at the top of each cycle. Calcareous nannofossils in subsurface Shark River sections indicate Zones NP 14 through NP 18 (Martini, 1971) (middle Eocene and early late Eocene).
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).
Unnamed Formation at Cape May (upper Pliocene): Unnamed Formation at Cape May - Interbedded gravel, sand, and clay, massive to thickbedded. Informal unit described from a corehole at the Cape May Airport. The lower 18.3 m (60 ft) consists of interbedded gravel; medium- to very coarse grained, poorly sorted sand; and thin to thick beds of medium- to dark-gray, very woody clay. Gravel clasts are typically less than 0.64 mm (0.025 in) in diameter. The upper 12.2 m (40 ft) consists of a thick-bedded, medium-gray, extensively bioturbated clay-silt, which is overlain by an extensively burrowed, fine- to medium-grained glauconitic (about 5 percent) quartz sand. Quartz and siliceous rock fragments compose most sand grains. Feldspar is present in most samples but usually constitutes less than 10 percent of the sand fraction. No calcareous macrofossils were found in the burrowed intervals. Unit is known only to occur on the Cape May peninsula where it lies within a large channel. The unit is about 60 m (197 ft) in maximum thickness. The contact with the underlying Belleplain Member of the Kirkwood Formation is sharp and unconformable; a basal gravel bed as much as 1 m (3 ft) thick is present along the contact. The pollen assemblage in the lower part of the unit is dominated by pine and oak with somewhat lesser amounts of hickory and basswood. Spruce, hemlock, beech, alder, and black gum are minor constituents. Traces of fir, willow, birch, and sweet gum are present, as is exotic Engelhardia. The nonarborial pollen are a Multisia-type composite of the present-day Andean provenance which indicate an exotic cool climate. The lower assemblage suggests a cool-temperate climatic regimen. The pollen assemblage in the upper beds is dominated by oak and hickory with minor amounts of basswood, sweet gum, pine, and Multisia-type composite. Traces of cedar, willow, birch, alder, grass, and Sphagnum spores also are present. This assemblage probably represents a temperate climatic regimen (Les Sirkin, Adelphi University, written commun., 1991). The low percentage of exotic species is characteristic of the late Pliocene, and therefore, the unnamed unit at Cape May may be equivalent to the Beaverdam Formation of the Delmarva Peninsula of Delaware, Maryland, and Virginia.

New Mexico

Grayburg and Queen Fromations (Phanerozoic | Paleozoic | Permian): Grayburg and Queen Formations; sandstone, gypsum, anhydrite, dolomite, and red mudstone; Guadalupian
sedimentary units, Palogene (Phanerozoic | Cenozoic | Tertiary): Paleogene sedimentary units; includes Baca, Galisteo, El Rito, Blanco Basin, Love Ranch, Lobo, Sanders Canyon, Skunk Ranch, Timberlake, and Cub Mountain Formations
Yesa Formation (Phanerozoic | Paleozoic | Permian): Yeso Formation; sandstones, siltstones, anhydrite, gypsum, halite, and dolomite; Leonardian

Nevada

Continental deposits of siltstone, shale, conglomerate, and limestone (Cretaceous): CONTINENTAL DEPOSITS OF SILTSTONE, SHALE, CONGLOMERATE, AND LIMESTONE-Includes units such as King Lear Formation in Humboldt County, Newark Canyon Formation in Eureka County, Willow Tank Formation and baseline Sandstone in Clark County
Continental sedimentary rocks (Late Cretaceous to Eocene): CONTINENTAL SEDIMENTARY ROCKS-Includes units such as Pansy Lee Conglomerate in Humboldt County, part of Cretaceous(?) and Tertiary rocks of Kleinhampl and Ziony (1967) in northern Nye County, and part of "older clastic rocks" of Tschanz and Pampeyan (1970) in Lincoln County
Continental sedimentary rocks (Late Cretaceous to Early Miocene): CONTINENTAL SEDIMENTARY ROCKS-Clark County
Horse Spring Formation (Late Oligocene to Middle Miocene): HORSE SPRING FORMATION-Tuffaceous sedimentary rocks, southern Nevada
Sedimentary rocks (Late Cretaceous to Oligocene): SEDIMENTARY ROCKS-Includes Sheep Pass Formation (Eocene) and related units and unnamed tuffaceous sedimentary rocks
Tuffaceous sedimentary rocks (Late Eocene to Late Miocene): TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff
Tuffaceous sedimentary rocks (Early Oligocene to Early Miocene): TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff

New York

Brunswick Formation (Upper Triassic): Brunswick Formation - sandstone, siltstone and mudstone.
Brunswick Formation, undivided (Upper Triassic): Brunswick Formation, undivided - includes the units: TRbg: sandstone and conglomerate; TRbs: sandstone, siltstone, mudstone; TRba: mudstone, sandstone, and arkose.
Stockton Formation (Upper Triassic): Stockton Formation - arkose, conglomerate, and mudstone.

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.
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

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.
Ogallala Formation (Phanerozoic | Cenozoic | Tertiary | Pliocene): CIMARRON- Generally semiconsolidated clay, silt, sand, gravel, and caliche 0 to 400 feet thick. BEAVER- Interbedded sand, siltstone, clay, gravel lenses, and thin limestone. Caliche common near surface but occurrence is not limited to the surface. Caliche accounts for most of the white color in the Ogallala. Other colors generally light tan or buff but locally may be pastel shades of almost any color. The Laverne and Rexroad Formations of Pliocene age and the Meade Group and Odee (of local usage) and other formations of Pleistocene age occur locally and are included with the Ogallala Formation, 0-700 feet thick. WOODWARD- Gravel, sand, silt, clay, caliche, and limestone, locally cemented with calcium carbonate. Generally light-tan to gray to white. Thickness ranges up to 400 feet and probably averages 150 feet. CLINTON- Gray to light-brown, fine- to medium-grained sand with some, clay, silt, gravel, volcanic ash, and caliche beds; locally cemented by calcium carbonate. Thickness ranges from 0 to about 320 feet. The formation thins eastward.
Pleistocene and Pliocene deposits, undifferentiated (Phanerozoic | Cenozoic | Tertiary Quaternary | Pliocene Pleistocene): TEXAS- Interfingering beds, tongues, and lenses of sand, silt, clay, gravel, sandstone, caliche, limestone, conglomerate, and volcanic ash. Includes Ogallala and Laverne Formations of Pliocene age and younger deposits of Pleistocene age. Locally the units are tightly cemented by calcium carbonate; other places, they are very poorly consolidated and nearly free of cementing materials. Thickness ranges from 0 to about 800 feet.

Oregon

Lacustrine and fluvial deposits (Miocene) (Miocene): Poorly to moderately consolidated, bedded silicic ash and pumicite, diatomite, tuffaceous sedimentary rocks, minor mudflow deposits, and some coarse epiclastic deposits. Vitroclastic material in some beds diagenetically altered to zeolites, secondary silica minerals, and clay minerals. In eastern Blue Mountains province vertebrate fossils indicate unit is mostly of late Miocene (Clarendonian) age, but may also include some rocks of middle Miocene (Barstovian) age. In High Lava Plains and northern Owyhee Upland provinces, vertebrate fossils indicate unit is partly late Miocene (Clarendonian), but probably is mostly middle Miocene (Barstovian) in age. Interfingers and grades laterally into unit Tmb. Includes lake and stream sediments and tuffaceous lake and stream deposits of Prostka (1962, 1967), Deer Butte Formation of Corcoran and others (1962) and Kittleman and others (1967), Juntura Formation of Shotwell and others (1963), some rocks originally assigned to the lower part of the (now obsolete) Danforth Formation of Piper and others (1939), and interbeds in upper part of Columbia River Basalt Group in northern Wallowa County
Marine 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
Terrace, pediment, and lag gravels (Holocene and Pleistocene) (Pleistocene to Holocene): Unconsolidated deposits of gravel, cobbles, and boulders intermixed and locally interlayered with clay, silt, and sand. Mostly on terraces and pediments above present flood plains. Includes older alluvium of Smith and others (1982) in the Klamath Mountains and both high- and low-level terraces along Oregon coast. Includes dissected alluvial fan deposits northeast of Lebanon, and Linn and Leffler Gravels of Allison and Felts (1956)
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)
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

Allegheny Formation (Pennsylvanian): Allegheny Formation - Cyclic sequences of sandstone, shale, limestone, clay, and coal; includes valuable clay deposits and Vanport Limestone; commercially valuable Freeport, Kittanning, and Brookville-Clarion coals present; base is at bottom of Brookville-Clarion coal.
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.
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.
Hammer Creek Formation (Triassic): Hammer Creek Formation - Gray and pale red, fine- to coarse-grained quartzose sandstone, siltstone, and mudstone.
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.
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
Pensauken and Bridgeton Formations, undifferentiated (Tertiary): Pensauken and Bridgeton Formations, undifferentiated - Dark-reddish-brown, cross-stratified, feldspathic quartz sand and some thin beds of fine gravel and rare layers of clay or silt.
Scherr Formation (Devonian): Scherr Formation - Chiefly siltstone; some fine-grained sandstone, shale, and mudstone; light olive gray; marine fossils.
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

Chatham Group, undivided (Triassic): Chatham Group, undivided: conglomerate, sandstone and mudstone
Tidal Marsh (Quaternary): Tidal Marsh: Peat and muck deposits along tidal margins of esturaries and back bays. Deposits range from a few feet to 60+ feet deep. Locally include silt and fine sand and clay as levees on tidal channels. At depth peaty material may be accumulated from fresh water plants. Peat at the surface dominated by spartina and other salt tolerant species.

South Dakota

Belle Fourche Shale (Phanerozoic | Mesozoic | Cretaceous-Late): Dark-gray to black bentonitic shale containing minor limestone lenses, bentonite layers, fossiliferous calcarenite, and large, ferruginous, carbonate concretions. Thickness 150-350 ft (46-107 m).
Belle Fourche Shale, Mowry Shale, Newcastle Sandstone,and Skull Creek Shale (Phanerozoic | Mesozoic | Cretaceous-Early Cretaceous-Middle(?) Cretaceous-Late): Note: see individual unit descriptions
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
Java Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Early): Sand to gravel of fluvial orgin. Upper portion is tan to reddish-brown eolian silt with minor clay and fine-grained sand. Thickness up to 180 ft (55 m).
Morrison Formation, Unkpapa Sandstone, Sundance Formation, and Gypsum Spring Formation (Phanerozoic | Mesozoic | Jurassic-Middle Jurassic-Late): Morrison Formation (Late Jurassic)- Light-gray to green and variegatedred, brown, yellow, or lavender, silceous claystone, shale, and siltstone containing interbedded sandstone and fresh-water limestone lenses. Thickness up to 150 ft (46 m). Unkpapa Sandstone (Late Jurassic)- White, massive to thin-bedded, fine-grained, argillaceous sandstone. May be variegated to banded red, yellow, brown, or lavender. Thickness up to 267 ft (81 m). Sundance Formation (Late to Middle Jurassic)- Greenish-gray, yellow, tan, red to orange, and white, variegated, interbedded, fine- to coarse-grained sandstone, siltstone, clay, and limestone. Thickness 250-350 ft (76-107 m). Gypsum Springs Formation (Middle Jusassic)- Massive white gypsum and minor maroon siltstone and shale. Thickness up to 40 ft (12 m).
Niobrara Formation (Phanerozoic | Mesozoic | Cretaceous-Late): White to dark gray argillaceous chalk, marl, and shale. Weathers yellow to orange. Contains thin, laterally continuous bentonite beds, chalky carbonaceous shale, minor sand, and small concretions. Thickness 160-225 ft (49-69 m).
Ogallala Group (Phanerozoic | Cenozoic | Tertiary Quaternary | Miocene Pliocene(?) Pleistocene-Early): Includes: Ash Hollow Formation- White, tan, and gray, well-cemented, calcareous sandstone and silty limestone often referred to as "mortar beds". Thickness 90-250 ft 27-76 m) Valentine Formation- Gray, unconsolidated, fine- to coarse grained, fluvial siltstone, channel sandstone, and gravel derived from western sources. Thickness 175-225 ft (53-69 m). Fort Randall Formation- Pink and gray claystone with interbedded sandstone. Also includes green to gray orthoquartzite, bentonitic clay, and conglomerate. Thickness up to 130 ft (40 m).
Outwash, Undifferentiated (Phanerozoic | Cenozoic | Quaternary | Pleistocene [Upper Wisconsin]): Heterogeneous sand and gravel, with minor clay and silt. Deposits of glaciofluvial orgin including outwash plains, kame terraces, and other undifferentiated deposits. Thickness up to 30 ft (9m).
Outwash, Undifferentiated (Phanerozoic | Cenozoic | Quaternary | Pleistocene [Illinoian(?) Pre-Illinoian]): Heterogeneous sand and gravel with minor clay of glaciofluvial orgin. Thickness up to 90 ft (27 m).
Sioux Quartzite (Proterozoic | Paleoproterozoic): Pink, reddish to tan, siliceous, fine to coarse-grained, iron-stained orthoquartzite with minor conglomerate and mudstone layers. Estimated thickness greater than 1,000 ft (305 m).
White River Group (Phanerozoic | Cenozoic | Tertiary | Eocene Oligocene): Includes: Brule Formation (Oligocene)- White, pink, light-green, and light-brown, massive to thin-bedded, bentonitic claystone, tuffaceous siltstone, and well-bedded, calcareous, tuffaceous quartz sandstone. Thickness up to 150 ft (46 m). Chadron Formation (Eocene)- Upper beds are gray, light-brown to maroon bentonite, claystone, siltstone tuffaceous fine-grained sandstone, and local, silicified carbonate lenses. Basal portion consists of poorly cemented, white, coarse-grained arkose and conglomerate. Thickness up to 160 ft (49 m). Chamberlain Pass Formation (Eocene)- Pale olive to pale red, mottled mudstone containing white, cross-bedded channel sandstone with basal conglomerate. Thickness up to 32 ft (10 m). Slim Buttes Formation (Eocene)- White, grayish- to yellowish-orange,pale-red to pink siltstone, clayey siltstone, bentonitic claystone,medium- to fine-grained sandstone, and conglomerate. Thickness up to 48 ft (15 m).

Tennessee

Alluvial deposits (Quaternary): Alluvial Deposits - Sand, silt, clay and gravel. Mapped only in valley of Cumberland River and in Elk Valley. Thickness generally less than 30 feet.
Alluvial deposits (Quaternary): Alluvial Deposits - Sand, silt, clay, and gravel. As much as 60 feet thick in flood plains of Tennessee and Cumberland Rivers; in smaller streams generally less than 20 feet thick.
Alluvial deposits (Quaternary): Alluvial Deposits - Sand, silt, clay, and gravel. In flood plain of Mississippi River more than 100 feet thick; in smaller streams generally less than 20 feet thick.
Devonian Formations, includes Pegram Formation, Camden Formation, Harriman Formation, Flat Gap Limestone, and Ross Formation (Devonian): Devonian Formations - Characterized by marked north-south facies variations. Because of pre-Chattanooga and/or pre-Cretaceous warping and erosion, the distribution and thickness of Devonian formations is very irregular. Includes Pegram Formation - Thick-bedded, gray limestone and gray sandstone. Thickness 0 to 15 feet; Camden Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. Thickness 0 to about 100 feet; Harriman Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. (Harriman and Camden are differentiated paleontologically.) Thickness 0 to 50 feet; Flat Gap Limestone - Thick-bedded, coarse-grained limestone, gray with red and brown grains. Thickness 0 to 55 feet; Ross Formation - Siliceous limestone; gray and variegated shale; and medium-grained glauconitic limestone. Thickness 0 to 75 feet.
Devonian Formations, including Pegram Formation, Camden Formation, Harriman Formation, Flat Gap Limestone, and Ross Formation (Devonian): Devonian Formations - Characterized by marked north-south facies variations and by very irregular distribution. Individual formations are not uniform in thickness and have been truncated by pre-Chattanooga erosion; includes Pegram Formation - Thick-bedded, gray limestone and gray sandstone. Thickness 0 to 30 feet; Camden Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. Thickness 0 to about 100 feet; Harriman Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. (Harriman and Camden are differentiated paleontologically.) Thickness 0 to 50 feet; Flat Gap Limestone - Thick-bedded, coarse-grained limestone, gray with red and brown grains. Thickness 0 to 13 feet; Ross Formation - Siliceous limestone; gray and variegated shale; and medium-grained glauconitic limestone. Thickness 0 to 75 feet.
High-level alluvial deposits (Quaternary-Tertiary): High-level Alluvial Deposits - Iron-stained gravel, sand, silt, and clay; variable in thickness but generally less then 60 feet thick.
High-Level Alluvial Deposits (Quaternary-Tertiary): High-Level Alluvial Deposits - Iron-stained gravel, sand, silt, and clay; variable in thickness but generally less than 60 feet thick.
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.
Shady Dolomite (Cambrian): Shady Dolomite - Light-gray, well-bedded dolomite with thin- to medium-bedded gray limestone; yellowish-brown residual clays with "jasperoid" diagnostic. Thickness about 1,000 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.
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.
Tuscaloosa Formation (Cretaceous): Tuscaloosa Formation - Poorly sorted, light-gray chert gravel in a matrix of silt and sand; locally interbedded with sand and clay lenses. Thickness 0 to 140 feet.
Tuscaloosa Formation (Cretaceous): Tuscaloosa Formation - Poorly sorted, light-gray chert gravel in a matrix of silt and sand; locally interbedded with sand and clay lenses. Thickness 0 to 150 feet.

Texas

alkali flat deposits (Phanerozoic | Cenozoic | Quaternary | Holocene): alkali flat deposits
alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene): alluvium
Austin Chalk (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]): Austin Chalk
barrier ridge and barrier flat deposts (Phanerozoic | Cenozoic | Quaternary | Holocene): barrier ridge and barrier flat deposts
Beaumont Formation, areas predominantly sand (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Late): Beaumont Formation, areas predominantly sand
Bigford Formation (Phanerozoic | Cenozoic | Tertiary | Eocene): Bigford Formation
Blackwater Draw Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene): Blackwater Draw 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
clay dune (Phanerozoic | Cenozoic | Quaternary | Holocene): clay dune
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.
Deweyville Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene (?)): Deweyville Formation
Eagle Ford Formation and Woodbine Formations, undivided (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]): Eagle Ford Formation and Woodbine Formations, undivided
fill and spoil (Phanerozoic | Cenozoic | Quaternary | Holocene): fill and spoil
Fort Worth Limestone and Duck Creek Formation, undivided (Phanerozoic | Mesozoic | Cretaceous-Early): Fort Worth Limestone and Duck Creek Formation, undivided
Goliad Formation (Phanerozoic | Cenozoic | Tertiary | Miocene): Goliad 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
Leona Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene): Leona Formation
Lingos Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Middle(?) Pleistocene-Late(?) Holocene): Lingos Formation
Lissie Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Middle): Lissie Formation
Midway Group, undivided (Phanerozoic | Cenozoic | Tertiary | Paleocene): Midway Group, undivided
Ogallala Formation (Phanerozoic | Cenozoic | Tertiary | Pliocene Miocene): Ogallala Formation
Onion Creek Marl (Phanerozoic | Cenozoic | Quaternary | Pleistocene): Onion Creek Marl
Pawpaw Formation, Weno Limestone, and Denton Clay, undivided (Phanerozoic | Mesozoic | Cretaceous-Early): Pawpaw Formation, Weno Limestone, and Denton Clay, undivided
Pecan Gap Chalk (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]): Pecan Gap Chalk
Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation (Phanerozoic | Cenozoic | Tertiary | Oligocene): Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation
Quaternary deposit, undivided (Phanerozoic | Cenozoic | Quaternary): sand, silt, clay, and gravel. locally indurated with calcium carbonate (caliche); includes point bar, natural levee, stream channel, sand dune, terrace, alluvial fan, landslide bolson and playa deposits
Queen City Sand (Phanerozoic | Cenozoic | Tertiary | Eocene): Queen City Sand
San Miguel Formation (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]): San Miguel Formation
Seymour Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Middle [Irvingtonian]): Seymour Formation
Strawn Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Atoka Des Moines]): Strawn Group
Sue Peaks Formation (Phanerozoic | Mesozoic | Cretaceous-Early): Sue Peaks Formation
Terrace deposits (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene): Terrace deposits
Thrifty and Graham Formations, undivided (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Virgil]): Thrifty and Graham Formations, undivided
Torcer Formation (Phanerozoic | Mesozoic | Cretaceous-Early): Torcer Formation
Tule Formation (Phanerozoic | Cenozoic | Quaternary | Pleistocene): Tule 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
Wellborn Formation (Phanerozoic | Cenozoic | Tertiary | Eocene): Wellborn Formation
Wilcox Group, undivided (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene): Wilcox Group, undivided
Wolfe City Formation (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]): Wolfe City Formation
Woodbine Formation (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]): Woodbine Formation

Utah

Cambrian quartzite in Logan-Huntsville Allochthon (Early to Middle Cambrian)
Cretaceous (2) sedimentary rocks in Logan-Huntsville Allochthon (Late Cretaceous)
Cretaceous (3) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Late Cretaceous)
Devonian sedimentary rocks in Logan-Huntsville Allochthon (Devonian)
Devonian sedimentary rocks in western Utah (Devonian to Mississippian)
Jurassic (1) sedimentary rocks in southeastern Utah (Middle 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)
Triassic (1) sedimentary rocks in Logan-Huntsville Allochthon (Early Triassic)
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

Bacons Castle Formation (Tertiary): Bacons Castle Formation - Gravel grading upward into sand and sandy clayey silt
Charles City Formation (Quaternary): Charles City Formation - Interbedded sand, silt, clay and minor gravel; at altitudes to 70-80 ft. (top of unit).
Chesapeake Group (Tertiary): Chesapeake Group - Fine- to coarse-grained sand, silt, clay; variably shelly and diatomaceous
Chuckatuck Formation (Quaternary): Chuckatuck Formation - Interbedded gravel, sand, silt, clay, and minor peat; at altitudes to 50-60 ft. (top of unit).
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.
Miocene Sand and Gravel (Tertiary): Miocene Sand and Gravel - Sandy gravel, sand, silt, and clay.
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
Moorings Unit of Oaks and Coch (1973) (Tertiary): Moorings Unit of Oaks and Coch (1973) - Sand, silt, and clay; at altitudes from 100-130 ft. (top of unit).
Omar Formation - Accomack Member: (Quaternary): Omar Formation - Accomack Member: sand, gravel, silt, clay, and peat; at altitudes to 50 ft.
Pennington Group (Mississippian): Pennington Group - Shale, sandstone, dusky-red mudstone, conglomerate, siltstone, and limestone.
Pliocene Sand and Gravel (Tertiary): Pliocene Sand and Gravel - Sandy gravel, gravelly sand, poorly to well-sorted sands, and thin- to medium-beds of clay and silt, at altitudes from 170-320 ft. (top of unit).
Quaternary and Tertiary Deposits (Tertiary-Quaternary): Quaternary and Tertiary Deposits - Tabb through Windsor Formations and alluvial/tidal prism deposits.
Shirley Formation (Quaternary): Shirley Formation - Interbedded gravel, sand, silt, clay, and peat; at altitudes to 35-45 ft. (top of unit).
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.
Windsor Formation (Tertiary-Quaternary): Windsor Formation - Interbedded gravel, sand, silt, and clay; at altitudes to 85-95 ft. (top of unit).

Washington

Eocene-Oligocene volcanic rocks (Eocene-Oligocene): Predominantly light-green, bedded andesite breccia with interbedded andesite and basalt flows, mudflows, and tuff beds; becomes more tuffaceous near top of unit. Includes tuffaceous and arkosic sandstone, shale, and carbonaceous shale beds in central and southern Cascade Mountians. Rhyodacite and quartz latite flows in northwestern Ferry County.
Eolian deposits (Holocene): Active dune sand; includes beach sand along southwestern Washington coast.
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.
Older glacial drift (Pleistocene): Till, outwash, and associated interglacial deposits; sorted and unsorted gravel, sand, silt, and clay. Includes peat beds and non-glacial sediments locally. Mostly pre-Wisconsin in age.
Oligocene marine rocks (Late Eocene to Late Oligocene): Massive, tuffaceous and nontuffaceous sandstone and siltstone; locally concretionary; includes conglomerate along the north coast of Olympic Peninsula and basaltic sandstone east of Chehalis.
Oligocene nonmarine rocks (Oligocene): Andesite conglomerate, tuff beds, and mudflow material. Includes some interbedded andesite flows in Columbia River Gorge. Lake sediments with Oligocene flora in Republic area in Ferry County. Massive tuffaceous sandstone and siltstone with beds of coal and high-alumina clay in Castle Rock-Toledo coal district in Cowlitz and Lewis Counties; include local interbedded basalt flows and some marine and late Eocene rocks.
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

Portage Lake Volcanics (Middle Proterozoic): Portage Lake Volcanics - Lava flows, mostly basalt, andesite and felsite flows and subordinate interflow sedimentary rocks.

West Virginia

Maccrady Formation (Mississippian): Maccrady Formation - red shale and mudrock, red and green sandstone, and minor limestone. Present only from Pendleton County southward. Contains rock salt and gypsum in southwestern Virginia.
Maccrady Formation and Pocono Group, undivided (Mississippian): Maccrady Formation and Pocono Group, undivided - Maccrady Formation: red shale and mudrock, red and green sandstone, and minor limestone. Present only from Pendleton County southward. Contains rock salt and gypsum in southwestern Virginia. Pocono Group: predominantly hard gray massive sandstones, with some shale. In the Eastern Panhandle, has been divided into the Hedges, Purslane, and Rockwell Formations.

Wyoming

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.