Geologic units in Lincoln county, Wyoming

Additional scientific data in this geographic area

Alluvium and Colluvium (Pleistocene-Holocene) at surface, covers 10 % of this area

Clay, silt, sand, and gravel in flood plains, fans, terraces, and slopes.

Stump Formation, Preuss Sandstone or Redbeds, and Twin Creek Limestone (Middle Jurassic-Upper Jurassic) at surface, covers 8 % of this area

Stump Formation - Glauconitic siltstone, sandstone, and limestone. Preuss Sandstone or Redbeds - Purple, maroon, and reddish-gray sandy siltstone and claystone; contains salt and gypsum in thick beds in some subsurface sections. Twin Creek Limestone - Greenish-gray shaly limestone and limy siltstone. Includes Gypsum Spring Member.

Wasatch Formation (Eocene) at surface, covers 7 % of this area

(Thrust Belt) Main body--Variegated red to gray, brown, and gray mudstone and sandstone; conglomeratic lenses. (in southwest Wyoming) - Drab to variegated claystone and siltstone, carbonaceous shale and coal, buff sandstone, arkose, and conglomerate. In northwestern part of Green River Basin is thick arkosic light-yellowish-tan sandstone intertonguing with pale-green to gray claystone and shale. (in east Wyoming) - Drab sandstone and drab to variegated claystone; numerous coal beds in lower part.

Green River Formation - Laney Member (Eocene) at surface, covers 7 % of this area

Oil shale and marlstone.

Ankareh Formation, Thaynes Limestone, Woodside Shale, and Dinwoody Formation (Lower Triassic-Upper Triassic) at surface, covers 6 % of this area

Ankareh Formation - Red and maroon shale and purple limestone. Thaynes Limestone - Gray limestone and limy siltstone. Woodside Shale - Red siltstone and shale. Dinwoody Formation - Gray to olive-drab dolomitic siltstone.

Green River and Wasatch Formations (Eocene) at surface, covers 6 % of this area

Green River Formation (Thrust Belt) - Buff laminated marlstone and limestone, brown oil shale, and siltstone. Includes Angelo and Fossil Butte Members. Wasatch Formation (Thrust Belt) - Variegated mudstone and sandstone. Includes Tunp and Bullpen Members, other tongues and unnamed members, and main body (variegated red to gray, brown, and gray mudstone and sandstone; conglomerate lenses). Green River Formation (in southwest Wyoming) - Oil shale, light-colored tuffaceous marlstone, and sandstone. Wasatch Formation (in southwest Wyoming) - Drab to variegated claystone and siltstone, carbonaceous shale and coal, buff sandstone, arkose, and conglomerate. In northwestern part of Green River Basin is thick arkosic light-yellowish-tan sandstone intertonguing with pale-green to gray claystone and shale.

Gannett Group (Lower Cretaceous) at surface, covers 6 % of this area

Red sandy mudstone, sandstone, and chert-pebble conglomerate; thin limestone and dark-gray shale in upper part, more conglomeratic in lower part. Includes Smoot Formation (red mudstone and siltstone), Draney Limestone, Bechler Conglomerate, Peterson Limestone, and Ephraim Conglomerate. Upper Jurassic fossils have been reported from the Ephraim.

Bridger Formation (Eocene) at surface, covers 5 % of this area

Greenish-gray, olive-drab, and white tuffaceous sandstone and claystone; lenticular marlstone and conglomerate.

Aspen Shale (Lower Cretaceous) at surface, covers 3 % of this area

Light- to dark-gray siliceous tuffaceous shale and siltstone, thin bentonite beds, and quartzitic sandstone.

Nugget Sandstone (Jurassic(?) and Triassic(?)) at surface, covers 3 % of this area

(Thrust Belt) - Buff to pink crossbedded well-sized and well-sorted quartz sandstone and quartzite; locally has oil and copper-silver-zinc mineralization. (North Wyoming) - Gray to dull-red, crossbedded quartz sandstone.

Sage Junction, Quealy, Cokeville, Thomas Fork, and Smiths Formations (Lower Cretaceous) at surface, covers 3 % of this area

Sage Junction Formation - Gray and tan siltstone and sandstone. Quealy Formation - Variegated mudstone and tan sandstone. Cokeville Formation - Tan sandstone, claystone, limestone, bentonite, and coal. Thomas Form Formation - Variegated mudstone and gray sandstone. Smiths Formation - Ferruginous black shale and tan to brown sandstone.

Hillard Shale (Upper Cretaceous) at surface, covers 3 % of this area

Dark-gray to tan claystone, siltstone, and sandy shale.

Green River Formation - Wilkins Peak Member (Eocene) at surface, covers 3 % of this area

Green, brown, and gray tuffaceous sandstone, shale, and marlstone; contains evaporites in subsurface sections.

Madison Group, Darby Formation, Three Forks and Jefferson Formations (Upper Devonian-Upper Mississippian) at surface, covers 2 % of this area

Madison Limestone or Group (Thrust Belt, North Wyoming and Northern Yellowstone area) - Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). Darby Formation (Thrust Belt and North Wyoming) - Yellow and greenish-gray shale and dolomitic siltstone underlain by fetid brown dolomite and limestone. Three Forks Formation (Northern Yellowstone area) - Pink, yellow, and green dolomitic siltstone and shale. Jefferson Formation (Northern Yellowstone area) - Massive siliceous dolomite.

Gravel, pediment, and fan deposits (Pleistocene-Holocene) at surface, covers 2 % of this area

Mostly locally derived clasts. Includes some glacial deposits along east flank of Wind River Range. Locally includes some Tertiary gravels.

Wells and Amsden Formations, Casper Formation, and Madison Limestone (Upper Mississippian-Permian) at surface, covers 2 % of this area

Wells Formation (Thrust Belt) - Gray limestone interbedded with yellow limy sandstone. Amsden Formation (Thrust Belt) - Red and gray cherty limestone and shale, sandstone, and conglomerate. Casper Formation (North and South Wyoming) - Gray, tan, and red thick-bedded sandstone underlain by interbedded sandstone and pink and gray limestone. May include some Devonian(?) sandstone along east flank of Laramie Mountains. Madison Limestone (North and South Wyoming) - Includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite).

Wasatch Formation - Diamictite and sandstone (Eocene) at surface, covers 2 % of this area

Diamictite grades laterally into other members of the formation.

Frontier Formation (Upper Cretaceous) at surface, covers 2 % of this area

(Thrust Belt) - White to brown sandstone and dark-gray shale; oyster coquina in upper part; coal and lignite in lower part. (North and South Wyoming) - Gray sandstone and sandy shale.

Bear River Formation (Lower Cretaceous) at surface, covers 2 % of this area

Black shale, fine-grained brown sandstone, thin limestone, and bentonite beds.

New Fork Tongue of Wasatch and Fontenelle Tongue or Member of Green River (Eocene) at surface, covers 2 % of this area

New Fork Tongue - dull-red and green mudstone, brown sandstone, and thin limestone beds, merging southward in T. 23 N. with other units. Wasatch and Fontenelle Tongue or Member - oil shale, marlstone, limestone, and siltstone; occurs along Green and New Fork Rivers and on west side of Green River Basin from T. 33 N. south to and lensing out in T. 17 N.) of Green River.

Bighorn Dolomite, Gallatin Group, Gros Ventre Formation, Snowy Range Formation, Pilgrim Limestone, Park Shale, Meagher Limestone, Wolsey Shale, Flathead Sandstone, Whitewood Dolomite, and Winnipeg and Deadwood Formations (Middle Cambrian-Upper Ordovician) at surface, covers 2 % of this area

Bighorn Dolomite (Thrust Belt and North Wyoming) - Gray massive cliff-forming siliceous dolomite and locally dolomitic limestone. Bighorn Dolomite (Northern Yellowstone area) - Light-gray massive siliceous dolomite. Gallatin Limestone or Group (Thrust Belt) - Gray and tan limestone. Gallatin Limestone or Group (North Wyoming) - Blue-gray and yellow mottled hard dense limestone. Gallatin Group-Snowy Range Formation (Northern Yellowstone area) - Medium-gray limestone and underlying greenish-gray shale. Gallatin Group-Pilgrim Limestone (Northern Yellowstone area) - Blue-gray and yellow mottled hard limestone. Gros Ventre Formation (Thrust Belt) - Greenish-gray micaceous shale. Gros Ventre Formation (North Wyoming) - Soft green micaceous shale (Upper and Middle Cambrian Park Shale Member), underlain by blue-gray and yellow mottled hard dense limestone (Middle Cambrian Death Canyon Limestone Member), and soft green micaceous shale (Middle Cambrian Wolsey Shale Member). Park Shale (Northern Yellowstone area) - Green micaceous soft shale. Upper part may be Late Cambrian. Meagher Limestone (Northern Yellowstone area) - Blue-gray and yellow mottled hard limestone. Wolsey Shale (Northern Yellowstone area) - Green micaceous soft shale. Flathead Sandstone (Northern Yellowstone area and North Wyoming) - Dull-red quartzitic sandstone. Whitewood Dolomite (Northeast Wyoming) - Buff massive fossiliferous dolomite. Winnipeg Formation (Northeast Wyoming) - Pink to yellow siltstone and shale. Deadwood Formation (Northeast Wyoming) - Red and brown quartzitic sandstone.

Blind Bull Formation (Upper Cretaceous) at surface, covers 2 % of this area

Gray to tan conglomeratic sandstone, siltstone, claystone, coal, and bentonite.

Landslide deposits (Pleistocene-Holocene) at surface, covers 2 % of this area

Locally includes intermixed landslide and glacial deposits, talus, and rock-glacier deposits.

Fowkes Formation (Eocene) at surface, covers 1 % of this area

Light-colored tuffaceous sandstone and siltstone, locally conglomeratic. Locally designated by some as Norwood Tuff.

Glacial deposits (Pleistocene-Holocene) at surface, covers 1 % of this area

Till and outwash of sand, gravel, and boulders.

Phosphoria Formation and Related Rocks, Wells Formation, Amsden Formations, Quadrant Sandstone, and Tensleep Sandstone (Upper Mississippian-Permian) at surface, covers 1 % of this area

Phosphoria Formation and Related Rocks (Thrust Belt) - Upper part is dark- to light-gray chert and shale with black shale and phosphorite at top; lower part is black shale, phosphorite, and cherty dolomite. Phosphoria Formation and Related Rocks (Northern Yellowstone area) - Brown sandstone and dolomite, cherty phosphatic and glauconitic dolomite, phosphatic sandstone and dolomite, and greenish-gray to black shale. Intertonguing equivalent is Shedhorn Sandstone. Phosphoria Formation and Related Rocks (North Wyoming) - Brown sandstone and dolomite, cherty phosphatic and glauconitic dolomite, phosphatic sandstone and dolomite, and greenish-gray to black shale. Intertonguing equivalents of parts of Phosphoria are Park City Formation (primarlily cherty dolomite, limestone, and phosphatic gray shale) and Shedhorn Sandstone. Wells Formation - Gray limestone interbedded with yellow limy sandstone. Amsden Formation (Thrust Belt) - Red and gray cherty limestone and shale, sandstone, and conglomerate. Amsden Formation (Northern Yellowstone area) - Red and green dolomitic shale, siltstone, and sandstone. Amsden Formation (North Wyoming) - Red and green shale and dolomite; at base is brown sandstone. Quadrant Sandstone - Light-gray sandstone. Tensleep Sandstone - White to gray sandstone containing thin limestone and dolomite beds. Permian fossils have been found in the topmost beds of the Tensleep at some localities in Washakie Range, Owl Creek Mountains, and southern Bighorn Mountains.

Nugget Sandstone, Ankareh Formation, Thaynes Limestone, Woodside Shale, Chugwater, and Dinwoody Formation (Lower Triassic to Jurassic(?) and Triassic(?)) at surface, covers 1 % of this area

Nugget Sandstone (Thrust Belt) - Buff to pink crossbedded well-sized and well-sorted quartz sandstone and quartzite; locally has oil and copper-silver-zinc mineralization. Nugget Sandstone (North Wyoming) - Gray to dull-red, crossbedded quartz sandstone. Ankareh Formation - Red and maroon shale and purple limestone. Thaynes Limestone - Gray limestone and limy siltstone. Woodside Shale - Red siltstone and shale. Dinwoody Formation (Thrust Belt) - Gray to olive-drab dolomitic siltstone. Dinwoody Formation (North Wyoming) - Olive-drab hard dolomitic thin-bedded siltstone. Chugwater Formation - Red siltstone and shale. Alcova Limestone Member in upper middle part in north Wyoming. Thin gypsum partings near base in north and northeast Wyoming.

Evanston Formation (Upper Cretaceous-Paleocene) at surface, covers 1 % of this area

Gray siltstone, sparse red sandstone, and lignite beds.

Teewinot Formation (Miocene) at surface, covers 0.9 % of this area

White lacustrine clay, tuff, and limestone. In thrust belt includes conglomerate.

Phosphoria Formation and Related Rocks (Permian) at surface, covers 0.8 % of this area

(Thrust Belt) - Upper part is dark- to light-gray chert and shale with black shale and phosphorite at top; lower part is black shale, phosphorite, and cherty dolomite. (North Wyoming) - Brown sandstone and dolomite, cherty phosphatic and glauconitic dolomite, phosphatic sandstone and dolomite, and greenish-gray to black shale. Intertonguing equivalents of parts of Phosphoria are Park City Formation (primarily cherty dolomite, limestone, and phosphatic gray shale) and Shedhorn Sandstone.

Terrace gravel (Pliocene-Pleistocene) at surface, covers 0.8 % of this area

Partly consolidated gravel above and flanking some major streams.

Adaville Formation (Upper Cretaceous) at surface, covers 0.6 % of this area

Gray sandstone, siltstone, and carbonaceous claystone; conglomeratic in upper part; coal-bearing in lower part.

Wasatch Formation - La Barge and Chappo Members (Paleocene-Eocene) at surface, covers 0.3 % of this area

Red, gray, and brown mudstone and conglomerate and yellow sandstone. La Barge Member tongues out to north at about T. 35 N. Lower part of Chappo is Paleocene.

Salt Lake Formation (Miocene-Pliocene) at surface, covers 0.3 % of this area

White, gray, and green limy tuff, siltstone, sandstone, and conglomerate.

Dune sand and loess (Pleistocene-Holocene) at surface, covers 0.3 % of this area

Includes active and dormant sand dunes. In northwestern Wyoming is chiefly loess (age 12,000-19,000 years).

Conglomerate of Sublette Range (Paleocene-Eocene) at surface, covers < 0.1 % of this area

Locally derived indurated angular conglomerate.

Wasatch Formation - Cathedral Bluffs Tongue (Eocene) at surface, covers < 0.1 % of this area

Variegated claystone and lenticular sandstone; conglomeratic near south margin of Wind River Range.

Sedimentary rocks (Cretaceous). (Cretaceous) at surface, covers < 0.1 % of this area

Marine and deltaic sandstone and shale of Cordilleran foreland basin (includes Gannett Group, Frontier, Mowry, Kootenay, and Thermopolis formations) in eastern Idaho thrust belt. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

Laketown Dolomite (Middle Silurian-Upper Silurian) at surface, covers < 0.1 % of this area

Light-gray thick-bedded finely crystalline dolomite.

Wayan and Smiths Formations (Lower Cretaceous) at surface, covers < 0.1 % of this area

Wayan Formation - Variegated mudstone, siltstone, and sandstone. Smiths Formation - Ferruginous black shale and tan to brown sandstone.

Madison Limestone or Group (Lower Mississippian-Upper Mississippian) at surface, covers < 0.1 % of this area

Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite).

Sedimentary rocks (Jurassic). (Jurassic) at surface, covers < 0.1 % of this area

Marginal marine and marine sandstone and limestone; includes Nugget, Twin Creek, Preuss, Morrison, and Stump formations in eastern Idaho thrust belt. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

Madison Limestone, Darby Formation, Bighorn Dolomite, Gallatin Limestone, Gros Ventre Formation, and Flathead Sandstone, Cambrian rocks, Minnekahta Limestone, Opeche Shale, Minnelusa Formation, Pahasapa and Englewood Limestones, Whitewood Dolomite, and Winnipeg and Deadwood Formations (Cambrian-Permian) at surface, covers < 0.1 % of this area

Madison Limestone or Group (North and South Wyoming) - Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). Darby Formation (North Wyoming) - Yellow and greenish-gray shale and dolomitic siltstone underlain by fetid brown dolomite and limestone. Bighorn Dolomite (North Wyoming) - Gray massive cliff-forming siliceous dolomite and locally dolomitic limestone. Gallatin Limestone or Group (North Wyoming) - Blue-gray and yellow mottled hard dense limestone. Gros Ventre Formation (North Wyoming) - Soft green micaceous shale (Upper and Middle Cambrian Park Shale Member), underlain by blue-gray and yellow mottled hard dense limestone (Middle Cambrian Death Canyon Limestone Member), and soft green micaceous shale (Middle Cambrian Wolsey Shale Member). Flathead Sandstone (North Wyoming) - Dull-red quartzitic sandstone. Cambrian Rocks (South Wyoming) - On south flank of Granite Mountains, blue-gray and yellow mottled hard dense limestone interbedded with soft green micaceous shale; dull-red quartzitic sandstone at bae. On and south of Rawlins uplift, glauconitic quartzitic sandstone. Minnekahta Limestone (Northeast Wyoming) - Gray slabby hard limestone. Locally is a member of the Goose Egg Formation. Opeche Shale (Northeast Wyoming) - Red soft sandy shale. Locally is a member of the Goose Egg Formation. Minnelusa Formation (Northeast Wyoming) - Buff and red limy sandstone; some thin limestone beds, solution breccias, and gypsum. Pahasapa Limestone (Northeast Wyoming) - Gray massive dolomititc limestone. Englewood Limestone (Northeast Wyoming) - Pink slabby dolomitic limestone. Whitewood Dolomite (Northeast Wyoming) - Buff massive fossiliferous dolomite. Winnipeg Formation (Northeast Wyoming) - Pink to yellow siltstone and shale. Deadwood Formation (Northeast Wyoming) - Red and brown quartzitic sandstone. Paleozoic Rocks, undifferentiated (Thrust Belt).

Intrusive and extrusive igneous rocks (Miocene-Pliocene) at surface, covers < 0.1 % of this area

Composition ranges from hornblende monzonite to basalt. In Yellowstone area includes andesite and basalt of Emerald Lake (age about 2 Ma), rhyolite of Broad Creek, Pliocene Junction Butte Basalt, and gravel of Mount Everts. Age of basalt on Crescent Mountain 3.6 Ma.

Older alluvial deposits (Quaternary) at surface, covers < 0.1 % of this area

Older alluvial deposits

Sedimentary rocks associated with Basin and Range extension. (Quaternary, Pliocene, and Miocene) at surface, covers < 0.1 % of this area

Fluvial, fan, and lacustrine deposits and intercalated volcanic rocks of the Basin and Range Province (~16-2 Ma); consolidated to weakly consolidated sandstone, siltstone, arkose, conglomerate, mudstone, tuffaceous sediment, basalt, basaltic tephra, and rhyolite tuff. Includes deposits of Lake Idaho (Idaho Group) in western Snake River Plain and Salt Lake Formation deposited in Basin and Range Province of east-central Idaho. (Quaternary to Eocene Continental Sediments and Sedimentary Rocks).

Beirdneau Sandstone, Hyrum Dolomite, and Water Canyon Formation (Devonian) at surface, covers < 0.1 % of this area

Beirdneau Sandstone, Hyrum Dolomite, and Water Canyon Formation.

Alluvium and colluvium (Quaternary) at surface, covers < 0.1 % of this area

Alluvium and colluvium

Alluvial deposits. (Quaternary) at surface, covers < 0.1 % of this area

Deposits in valleys consisting of gravel, sand, and silt. Includes younger terrace deposits. May contain some glacial deposits and colluvium in uplands. (Quaternary Sediments).

Undivided surficial deposits (Pleistocene-Holocene) at surface, covers < 0.1 % of this area

Mostly alluvium, colluvium, and glacial and landslide deposits. Primarily in Yellowstone area and Bighorn Mountains.

Alluvial-fan deposits. (Quaternary) at surface, covers < 0.1 % of this area

Gravel and subordinate sand and silt deposited at mouths of canyons; largest fans are in Basin and Range Province in east-central and southeastern Idaho. (Quaternary Sediments).

Camp Davis Formation (Miocene) at surface, covers < 0.1 % of this area

Upper 5,000 ft chiefly red conglomerate and red claystone; underlain by white tuff, limestone, claystone, and basal gray conglomerate.

Wasatch Formation (Late Paleocene to Early Eocene) at surface, covers < 0.1 % of this area

Wasatch Formation.

Sedimentary rocks (Mississippian). (Mississippian) at surface, covers < 0.1 % of this area

Marine limestone of Mississippian carbonate banks and turbiditic sandstone, mudstone, and conglomerate of Antler flysch trough; includes Madison and Lodgepole formations and Chesterfield Range Group of southeastern Idaho; McGowan Creek Formation, White Knob Limestone, and overlying carbonate bank of Lost River Range; and Copper Basin Group of Pioneer Mountains. Includes poorly dated Salmon River assemblage east of Stanley, consisting of argillite, siltstone, calcareous sandstone, and limestone. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

Fowkes Formation (Eocene) at surface, covers < 0.1 % of this area

Fowkes Formation.

Weber Quartzite (Pennsylvanian to Permian) at surface, covers < 0.1 % of this area

Weber Quartzite

Gardison and Lodgepole Limestones (Mississippian) at surface, covers < 0.1 % of this area

Gardison and Lodgepole Limestones.

Wasatch and Evanston? Formations undivided (Late Cretaceous to Early Eocene) at surface, covers < 0.1 % of this area

Wasatch and Evanston? Formations undivided.

Sedimentary rocks (Ordovician and Cambrian). (Ordovician and Cambrian) at surface, covers < 0.1 % of this area

Marine limestone, dolomite, and subordinate shale and sandstone of Cambrian carbonate bank of southeast Idaho stratigraphically up to St. Charles Formation and Ordovician Garden City Limestone. Includes Bayhorse succession (Cash Creek Quartzite, Garden Creek Phyllite, Bayhorse Dolomite, Ramshorn Slate, and Clayton Mine Quartzite) of Clayton area and Pioneer Mountains; quartzite of Kamiak Butte north of Moscow; and Cambrian Gold Creek quartzite, Rennie Shale, and Lakeview Limestone east of Bayview. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).