Geologic units in Teton county, Wyoming

Additional scientific data in this geographic area

Rhyolite flows, tuff, and intrusive igneous rocks (Pleistocene) at surface, covers 19 % of this area

Includes Plateau Rhyolite (age about 0.07 Ma) and interlayered sediments, Mount Jackson Rhyolite (age 0.6 to about 1 Ma), Lewis Canyon Rhyolite (age about 0.9 Ma); and Lava Creek Tuff of Yellowstone Group (age 0.6 to about 1 Ma).

Glacial deposits (Pleistocene-Holocene) at surface, covers 9 % of this area

Till and outwash of sand, gravel, and boulders.

Undivided surficial deposits (Pleistocene-Holocene) at surface, covers 8 % of this area

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

Alluvium and Colluvium (Pleistocene-Holocene) at surface, covers 8 % of this area

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

Landslide deposits (Pleistocene-Holocene) at surface, covers 7 % of this area

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

Madison Group, Darby Formation, Three Forks and Jefferson Formations (Upper Devonian-Upper Mississippian) at surface, covers 6 % 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.

Huckleberry Ridge Tuff of Yellowstone Group (Pliocene) at surface, covers 4 % of this area

Lavender to gray-brown welded rhyolite tuff.

Harebell Formation (Upper Cretaceous) at surface, covers 3 % of this area

Gold-bearing quartzite conglomerate, olive-drab sandstone, and green claystone.

Gravel, pediment, and fan deposits (Pleistocene-Holocene) at surface, covers 3 % of this area

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

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 3 % 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.

Pinyon Conglomerate (Upper Cretaceous-Paleocene) at surface, covers 3 % of this area

Brown gold-bearing quartzite conglomerate interbedded with brown and gray sandstone. Age of basal part about 67 Ma in northeastern Jackson Hole; farther south entire sequence is Paleocene.

Absaroka Volcanic Supergroup: Thorofare Creek Group - Two Ocean and Langford Formations (Eocene) at surface, covers 3 % of this area

Dark-colored andesitic volcaniclastic rocks and flows underlain by light-colored andesitic tuffs and flows. In places may include Trout Peak Trachyandesite of Sunlight Group.

Absaroka Volcanic Supergroup: Thorofare Creek Group - Wiggins Formation (Eocene) at surface, covers 2 % of this area

Light-gray volcanic conglomerate and white tuff, containing clasts of igneous rocks.

Nugget Sandstone, Ankareh Formation, Thaynes Limestone, Woodside Shale, Chugwater, and Dinwoody Formation (Lower Triassic to Jurassic(?) and Triassic(?)) at surface, covers 2 % 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.

Phosphoria Formation and Related Rocks, Wells Formation, Amsden Formations, Quadrant Sandstone, and Tensleep Sandstone (Upper Mississippian-Permian) at surface, covers 2 % 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.

Metasedimentary and metavolcanic rocks (Middle Archean-Late Archaen) at surface, covers 2 % of this area

Amphibolite, hornblende gneiss, biotite gneiss, quartzite, iron-formation, metaconglomerate, marble, and pelitic schist; locally preserved textures and structures suggest origin to be sedimentary or volcanic. Older than 2,875 Ma in Teton Range; older than 3,200 Ma in Granite Mountains; older than 2,600 Ma in Medicine Bow Mountains and Sierra Madre, where it is the Late Archean Phantom Lake Metamorphic Suite 3.

Granitic rocks of 2,600-Ma Age Group (Late Archean) at surface, covers 1 % of this area

Teton Range--Mount Owen Quartz Monzonite. Age 2,500+/- Ma; may be of Early Proterozoic age. Gros Ventre and Washakie Ranges--Granitic rocks. Yellowstone National Park, Owl Creek, Granite, and Seminoe Mountains, Rawlins uplift, and Medicine Bow Mountains--Granite. Wind River Range--Granodiorite to porphyritic and equigranular granite. Sierra Madre--Granite and granodiorite. Laramie Mountains--Granite, amphibolite, and minor amounts of metasedimentary rocks. Hartville uplift--Granite and quartz monzonite. Black Hills uplift--Granite and minor amounts of metasedimentary rocks.

Cloverly, Morrison, Sundance, and Gypsum Spring Formations (Middle Jurassic-Lower Cretaceous) at surface, covers 1 % of this area

Cloverly Formation - Rusty sandstone at top, underlain by brightly variegated bentonitic claystone; chert-pebble conglomerate locally at base. Morrison Formation - Dully variegated claystone, nodular limestone, and gray silty sandstone. In southern Yellowstone and Jackson Hole areas the presence of Morrison is questionable. Sundance Formation (Js) - Greenish-gray glauconitic sandstone and shale, underlain by red and gray nonglauconitic sandstone and shale. Gypsum Spring Formation - Interbedded red shale, dolomite, and gypsum. In north Wyoming wedges out south in T. 39 N.

Sohare Formation (Upper Cretaceous) at surface, covers 1 % of this area

Lenticular gray and brown sandstone and shale; thin coal beds.

Aspen Shale (Lower Cretaceous) at surface, covers 1.0 % of this area

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

Frontier Formation (Upper Cretaceous) at surface, covers 1.0 % 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.

Cody Shale (Late Cretaceous) at surface, covers 0.9 % of this area

(Northern Yellowstone area) - Gray to brown shale and siltstone. (North and South Wyoming) - Dull-gray shale, gray siltstone, and fine-grained gray sandstone.

Tensleep Sandstone and Amsden Formation (Upper Mississippian-Permian) at surface, covers 0.9 % of this area

Tensleep Sandstone (North Wyoming) - White to gray sandstone containing thin limestone and dolomite beds. Permian fossils have been found in the topmost beds of the Tensleep at some localities in Washakie Range, Owl Creek Mountains, and southern Bighorn Mountains. Amsden Formation (North Wyoming) - Red and green shale and dolomite; at base is brown sandstone. Tensleep Sandstone (Sorth Wyoming) - White to gray sandstone containing thin limestone and dolomite beds. Amsden Formation (South Wyoming) - Red and green shale and dolomite; at base is persistent red to brown sandstone.

Basalt flows and intrusive igneous rocks (Pleistocene) at surface, covers 0.9 % of this area

Yellowstone area--Includes Osprey, Madison River, Swan Lake Flat, and Falls River Basalts, basalts of Mariposa Lake, Undine Falls Basalt, and gravels, sands, silts, and basalts of The Narrows. In and adjacent to Absaroka and Washakie Ranges--Includes basalt of Lava Mountain (age about 0.5 Ma).

Bacon Ridge Sandstone (Upper Cretaceous) at surface, covers 0.7 % of this area

Gray to tan marine sandstone and thick coal beds; gold-bearing quartzite conglomerate in lower part.

Sohare Formation and Bacon Ridge Sandstone (Upper Cretaceous) at surface, covers 0.7 % of this area

Sohare Formation (Kso) - Lenticular gray and brown sandstone and shale; thin coal beds. Bacon Ridge Sandstone (Kb) - Gray to tan marine sandstone and thick coal beds; gold-bearing quartzite conglomerate in lower part.

Granite gneiss (Late Archean) at surface, covers 0.7 % of this area

Layered to massive, locally migmatitic; metasedimentary and metavolcanic rocks locally common. Includes Webb Canyon Gneiss in Teton Range.

Phosphoria Formation and Related Rocks (Permian) at surface, covers 0.6 % 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.

Absaroka Volcanic Supergroup: Thorofare Creek Group - Aycross Formation (Eocene) at surface, covers 0.6 % of this area

Brightly variegated bentonitic claystone and tuffaceous sandstone, grading laterally into greenish-gray sandstone and claystone. In and east of Jackson Hole contains gold-bearing lenticular quartzite conglomerate.

Mowry and Thermopolis Shales (Lower Cretaceous) at surface, covers 0.5 % of this area

Mowry Shale (Kmr) - Silvery-gray hard siliceous shale containing abundant fish scales and bentonite beds. Thermopolis Shale - Black soft fissile shale; Muddy Sandstone Member at top.

Chugwater and Dinwoody Formations (Lower Triassic-Upper Triassic) at surface, covers 0.5 % of this area

Chugwater Formation - Red siltstone and shale. Alcova Limestone Member in upper middle part. Thin gypsum partings near base. Dinwoody Formation - Olive-drab hard dolomitic thin-bedded siltstone.

Devils Basin Formation (Paleocene) at surface, covers 0.5 % of this area

Light-gray sandstone interbedded with green and gray claystone; sparse coal and carbonaceous shale.

Mesaverde Formation or Mesaverde Group (Upper Cretaceous) at surface, covers 0.4 % of this area

Mesaverde Formation (north Wyoming) - Light-colored massive to thin-bedded sandstone, gray sandy shale, and coal beds. In Jackson Hole locally contains gold-bearing quartzite conglomerate. North of North Fork Powder River east of the Bighorn Mountains, consists solely of the Parkman Sandstone Member. Mesaverde Group (South Wyoming) - Includes Almond Formation, Ericson Sandstone, Rock Springs and Blair Formations in Rock Springs uplift; Almond Formation (white and brown soft sandstone, gray sandy shale, coal and carbonaceous shale), Pine Ridge Sandstone (light-gray sandstone and thin coal beds), and Allen Ridge (gray sandstone, shale, and thin coal beds) and Haystack Mountains (gray marine sandstone and shale) Formations in Rawlins uplift; Pine Ridge Sandstone (light-gray sandstone and thin coal beds) and Rock River Formation (soft sandstone and sandy shale) in Laramie Basin.

Hoback Formation (Paleocene) at surface, covers 0.4 % of this area

Interbedded drab and gray sandstone and claystone. Locally contains thick red and gray conglomerate.

Bear River Formation (Lower Cretaceous) at surface, covers 0.4 % of this area

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

Wind River Formation (Eocene) at surface, covers 0.4 % of this area

Northwest Wyoming (Jackson Hole) - Variegated red and white claystone and siltstone; largely nontuffaceous except near the top; lenticular coal unit in middle. At base locally includes equivalent of Indian Meadows Formation. Central Wyoming - Variegated claystone and sandstone; lenticular conglomerate. Age of tuff at top 49 Ma.

Absaroka Volcanic Supergroup: Hominy Peak Formation (Eocene) at surface, covers 0.3 % of this area

Mafic volcaniclastic conglomerate and tuff; sparse claystone in upper part; gold-bearing quartzite conglomerate at base.

Teewinot Formation (Miocene) at surface, covers 0.3 % of this area

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

Stump Formation, Preuss Sandstone or Redbeds, and Twin Creek Limestone (Middle Jurassic-Upper Jurassic) at surface, covers 0.3 % 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.

Gannett Group (Lower Cretaceous) at surface, covers 0.2 % 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.

Camp Davis Formation (Miocene) at surface, covers 0.2 % of this area

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

Colter Formation (Miocene) at surface, covers 0.2 % of this area

Dull-green and gray tuff, volcanic conglomerate, and sandstone.

Conglomerate (Miocene-Pleistocene) at surface, covers 0.1 % of this area

Northwest Wyoming (Jackson Hole) (Pleistocene or Pliocene)--Paleozoic clasts, chiefly of Madison Limestone, in a lithified carbonate matrix; Central (Medicine Bow Mountains) and east Wyoming (east of Laramie Mountains) (Pleistocene to Miocene)--Giant granite boulders in an arkose matrix.

Cloverly and Morrison Formations or Inyan Kara Group (Upper Jurassic-Lower Cretaceous) at surface, covers 0.1 % of this area

Cloverly Formation (North and South Wyoming) - Rusty sandstone at top, underlain by brightly variegated bentonitic claystone; chert-pebble conglomerate locally at base. Cloverly Formation (Northeast Wyoming - Hartville Uplift) - Rusty to light-gray sandstone containing lenticular chert-pebble conglomerate interbedded with variegated bentonitic claystone. Morrison Formation (North and South Wyoming) - Dully variegated claystone, nodular limestone, and gray silty sandstone. In southern Yellowstone and Jackson Hole areas the presence of Morrison is questionable. Morrison Formation (Northeast Wyoming) - dully variegated siliceous claystone, nodular white limestone, and gray silty sandstone. Inyan Kara Group (Northeast - Black Hills) - Rusty to light-gray sandstone containing lenticular chert-pebble conglomerate interbedded with variegated bentonitic claystone. Includes Fall River and Lakota Formations.

Metamorphosed mafic and ultramafic rocks (Late Archean) at surface, covers 0.1 % of this area

Teton Range--Rendezvous Metagabbro; 2,875 Ma or older. Gros Ventre Range--Hornblende gneiss and serpentinite. Wind River Range--Pillowed amphibolite, metagabbro, and ultramafic sills. Wind River Canyon (cutting through Owl Creek Mountains)--Amphibolite and felsic gneiss of volcanic origin. Older than 2,700 Ma. Bighorn and Granite Mountains--Amphibolite. Seminoe Mountains--Amphibolite of volcanic origin, komatiite, and metagabbro. Casper Mountain--Amphibolite and serpentinite. Laramie Mountains--Amphibolite of volcanic origin, komatiite(?), metagabbro, and ultramafic sills.

Conant Creek Tuff (Miocene) at surface, covers 0.1 % of this area

Lavender rhyolite welded tuff.

Volcanic Conglomerate (Eocene) at surface, covers 0.1 % of this area

Dark-brown to black conglomerate, poorly bedded, composed chiefly of basalt clasts in a basaltic tuff matrix.

Sundance and Gypsum Spring Formations (Middle Jurassic-Upper Jurassic) at surface, covers < 0.1 % of this area

Sundance Formation (Js) - Greenish-gray glauconitic sandstone and shale, underlain by red and gray nonglauconitic sandstone and shale. Gypsum Spring Formation - Interbedded red shale, dolomite, and gypsum. In north Wyoming wedges out south in T. 39 N.

Absaroka Volcanic Supergroup: Sunlight Group - Trout Peak Trachyandesite (Eocene) at surface, covers < 0.1 % of this area

Trout Peak Trachyandesite.

Red Conglomerate on top of Hoback and Wyoming Ranges (Miocene) at surface, covers < 0.1 % of this area

Locally derived clasts of Mesozoic and Paleozoic rocks in a red clay and sand matrix.

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.

Intrusive igneous rocks (Eocene) at surface, covers < 0.1 % of this area

Felsic and mafic igneous bodies; the larger are mainly felsic.

Nugget Sandstone (Jurassic(?) and Triassic(?)) at surface, covers < 0.1 % 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.

Shooting Iron Formation (Pliocene) at surface, covers < 0.1 % of this area

Greenish-gray to pink tuffaceous lacustrine and fluviatile claystone and siltstone, fine-grained sandstone, and conglomerate.

Meeteetse Formation (Upper Cretaceous) at surface, covers < 0.1 % of this area

Chalky-white to gray sandstone, yellow, green, and dark-gray bentonitic claystone, white tuff, and thin coal beds.

Heart Lake Conglomerate (Pliocene) at surface, covers < 0.1 % of this area

Abundant gray limestone and dolomite clasts and sparse rhyolite and quartzite clasts in a talc and clay matrix.

Sundance and Gypsum Spring Formations and Nugget Sandstone (Jurassic(?) and Triassic(?) to Upper Jurassic) at surface, covers < 0.1 % of this area

Sundance Formation (Js) - Greenish-gray glauconitic sandstone and shale, underlain by red and gray nonglauconitic sandstone and shale. Gypsum Spring Formation - Interbedded red shale, dolomite, and gypsum. In north Wyoming wedges out south in T. 39 N. Nugget Sandstone (JTRn) - Gray to dull-red, crossbedded quartz sandstone.

Frontier Formation and Mowry and Thermopolis Shales (Lower Cretaceous-Upper Cretaceous) at surface, covers < 0.1 % of this area

Frontier Formation (Kf) - Gray sandstone and sandy shale. In Northern Yellowstone area, Yellowish- to medium-gray sandstone; tuffaceous and carbonaceous in lower part. Mowry Shale (Kmr) - Silvery-gray hard siliceous shale containing abundant fish scales and bentonite beds. Thermopolis Shale - Black soft fissile shale; Muddy Sandstone Member at top.

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

Locally derived indurated angular conglomerate.

Absaroka Volcanic Supergroup: Thorofare Creek and Sunlight Groups (Eocene) at surface, covers < 0.1 % of this area

Thorofare Creek Group - Light-colored volcaniclastic strata, andesite lava flows, and dark-brown breccia; Sunlight Group - including Trout Peak Trachyandesite, Wapiti Formation (andesitic volcaniclastic rocks), Crescent Hill Basalt, and Mount Wallace Formation (felsic and mafic volcaniclastic rocks).

Rhyolite (Pleistocene). (Pleistocene) at surface, covers < 0.1 % of this area

Rhyolite tuffs, flows, and domes; includes Yellowstone Group (2.0-0.6 Ma) and isolated domes on Snake River Plain and north of Soda Springs (less than 2.0 Ma). (Quaternary to Eocene Continental Volcanic and Intrusive Rocks).

Glacial deposits. (Pleistocene) at surface, covers < 0.1 % of this area

Till and outwash consisting of gravel, sand, silt, and clay. Formed by valley glaciers at higher elevations and by the Cordilleran ice sheet in northern Idaho. Includes deposits of several glacial episodes. Includes rock glacier deposits and some modern alluvium derived from reworked till and outwash. (Quaternary Sediments).

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

Marine phosphorite, shale, and chert of Phosphoria Formation, fine-grained sandstone and mudrock of Wells, Quadrant, Amsden, and Shedhorn formations, and fine-grained sandstone, carbonaceous mudstone, and limestone of the Snaky Canyon Formation and Sun Valley and Oquirrh groups. Located in south-central and eastern Idaho. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).