Geologic units in Missouri (state in United States)

Additional scientific data in this geographic area

Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (Early Ordovician-Ibexian Series) at surface, covers 16 % of this area

Fine crystalline, silty, cherty dolomite, and oolitic chert with local sandstone beds.

Osagean Series (Early Mississippian-Osagean Series) at surface, covers 11 % of this area

Keokuk Limestone, Burlington Limestone, Elsey Formation, Reeds Spring Formation, Pierson Limestone, Fern Glen Formation.

Marmaton Group (Middle Pennsylvanian-Middle Series-Desmonian Stage) at surface, covers 9 % of this area

Cyclic deposits, shale and limestone with sandstone, clay and several coal beds, some workable.

Cherokee Group - Cabaniss Subgroup, Krebs Subgroup (Middle Pennsylvanian-Middle Series-Desmonian Stage) at surface, covers 9 % of this area

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.

Roubidoux Formation (Early Ordovician-Ibexian Series) at surface, covers 9 % of this area

Sandstone, chert and interbedded dolomite

Holocene series (Quaternary-Holocene Series) at surface, covers 8 % of this area

Alluvium - clay, silt, sand, and gravel.

Gasconade Dolomite (Early Ordovician-Ibexian Series) at surface, covers 5 % of this area

Coarse - crystalline cherty dolomite with a basal Gunter Sandstone Member.

Kansas City Group (Late Pennsylvanian-Upper Series-Missourian Stage) at surface, covers 5 % of this area

Cyclic deposits, limestone and shale with minor sandstone and coal.

Riverton Formation, Burgner Formation (Middle Pennsylvanian-Atokan Stage) at surface, covers 4 % of this area

Shale, clay, coal. Burgner Formation - limestone.

Meramecian Series (Late Mississippian-Meramecian Series) at surface, covers 4 % of this area

St. Louis Limestone, Salem Formation, Warsaw Formation.

Eminence Dolomite, Potosi Dolomite (Late Cambrian-Croixian Series) at surface, covers 3 % of this area

Eminence Dolomite - dolomite with some druse - coated chert. Potosi Dolomite - dolomite with abundance of druse - coated chert.

Pleasanton Group (Late Pennsylvanian-Upper Series-Missourian Stage) at surface, covers 2 % of this area

Dominantly shale and sandstone with minor coal.

Lansing Group (Late Pennsylvanian-Upper Series-Missourian Stage) at surface, covers 2 % of this area

Cyclic deposits of limestone and shale.

Kinderhookian Series (Early Mississippian-Kinderhookian Series) at surface, covers 2 % of this area

Northview Shale, Sedalia Formation, Compton Limestone, Bachelor Formation Chouteau Group, Hannibal Shale, Horton Creek Limestone.

Shawnee Group (Late Pennsylvanian-Upper Series-Virgilian Stage) at surface, covers 2 % of this area

Cyclic deposits, limestone and shale with sandstone and siltstone.

Wabaunsee Group (Late Pennsylvanian-Upper Series-Virgilian Stage) at surface, covers 1 % of this area

Cyclic deposits, principally shale, sitlstone, sandstone with thin limestone beds and minor coal.

Pennsylvanian Undifferentiated (Pennsylvanian) at surface, covers 1 % of this area

Pennsylvanian Undifferentiated

Douglas Group (Late Pennsylvanian-Upper Series-Virgilian Stage) at surface, covers 0.8 % of this area

Cyclic deposits, dominantly shale with sandstone, and limestone.

Elvins Group - (including Derby-Doerun Dolomite, Davis Formation), Bonneterre Dolomite (Late Cambrian-Croixian Series) at surface, covers 0.7 % of this area

Derby-Doerun Dolomite - alternating thin dolomite, siltstone, and shale; Davis Formation - glauconitic shale with fine - grained sandstone, limestone, and dolomite); Bonneterre Dolomite - dolomite, dolomitic limestone, and limestone; glauconitic in lower part.

Decorah Group, Plattin Group (Middle Ordovician-Mohawkian Series) at surface, covers 0.6 % of this area

Decorah Group, Plattin Group

Leemon Formation, Maquoketa Group, Cape Limestone, Kimmswick Limestone, Noix-Cyrene Limestone, Maquoketa Shale (Late Ordovician to Middle Ordovician) at surface, covers 0.6 % of this area

Leemon Formation, Maquoketa Group including: (Girardeau Limestone, Orchard Creek Shale, Thebes Sandstone, Cape La Croix Shale), Cape Limestone, Kimmswick Limestone, Noix-Cyrene Limestone, Maquoketa Shale.

St. Peter Sandstone, Everton Formation (Middle Ordovician to Early Ordovician) at surface, covers 0.6 % of this area

St. Peter Sandstone, Everton Formation

Devonian System (Late to Early Devonian) at surface, covers 0.4 % of this area

Chattanooga Shale, Sylamore Sandstone, Fortune Formation, Holts Summit Sandstone, Snyder Creek Shale, Cedar Valley Limestone, Louisiana Limestone, Saverton Shale, Grassy Creek Shale, Turpin Sandstone, Bushberg Sandstone, Glen Park Limestone, St. Larent Limestone, Beauvais Sandstone, Grand Tower Limestone, Clear Creek Chert, Little Saline Limestone, Grassy Knob Chert, Bailey Formation.

St. Francois mountains volcanic supergroup (Precambrian Y) at surface, covers 0.4 % of this area

Chiefly alkali rhyolitic ash - flow tuffs, lava flows, and bedded tuffs, with minor trachytes.

Weldon River-Warrensburg-Moberly Channel Sandstone (Late Pennsylvanian-Upper Series-Missourian Stage) at surface, covers 0.4 % of this area

Weldon River-Warrensburg-Moberly Channel Sandstone.

Lamotte Sandstone (Late Cambrian-Croixian Series) at surface, covers 0.3 % of this area

Sandstone with some dolomitic and shaly lenses; coarse - graines to conglomeratic and arkosic at base.

Joachim Dolomite, Dutchtown Formation (Middle Ordovician-Mohawkian Series) at surface, covers 0.3 % of this area

Joachim Dolomite, Dutchtown Formation

Undifferentiated (Ordovician rocks) (Ordovician) at surface, covers 0.2 % of this area

Undifferentiated (Ordovician rocks)

Channel Sandstones (Pennsylvanian) at surface, covers 0.2 % of this area

Channel Sandstones

St. Francois Mountains intrusive suite (subvolcanic, alkali granitic ring complexes) (Precambrian Y) at surface, covers 0.2 % of this area

St. Francois Mountains intrusive suite (subvolcanic, alkali granitic ring complexes).

Tertiary system (Tertiary-Late-Pliocene to Paleocene) at surface, covers 0.2 % of this area

Pliocene series - Mounds Gravel (Lafayette Formation) - ferruginous, chert gravel, max of 60 ft. Eocene series - Wilcox group - includes Holly Springs Formation - bedded sandstone, clay and gravel, max of 1200 ft.; Ackerman Formation - clay with lens of sand and gravel, max of 100ft. Paleocene series - Midway Group - includes Porters Creek Clay - bentonitic clay, max of 200 ft.; Clayton Formation - marl, fossiliferous, calcareous, limonitic, glauconitic sand and clay, max of 20 ft.

Gulfian Series (Late Cretaceous-Gulfian) at surface, covers 0.2 % of this area

Owl Creek Formation - massive, sandy, micaceous, fossilliferous, glauconitic marine clay, max 100 ft. McNairy Formation - unconsolidated sandstone with clay and gravel lenses, max of 250 ft.

Silurian system (Late Silurian- to Early Silurian) at surface, covers 0.1 % of this area

Joliet Limestone, Bowling Green Dolomite, Bryant Knob Formation, Bainbridge Formation, Sexton Creek Limestone.

Chesterian Series (Late Mississippian-Chesterian Series) at surface, covers < 0.1 % of this area

Fayetteville Formation, Batesville Formation, Hindville Limestone, Vienna Limestone, Tar Springs Sandstone, Glen Dean Formation, Hardinsburg Formation, Golconda Formation, Cypress Formation, Paint Creek Formation, Yankeetown Sandstone, Renault Formation, Aux Vases Sandstone, Ste. Genevieve Limestone.

Cotter and Jefferson City Dolomites (Early Ordovician) at surface, covers < 0.1 % of this area

Cotter and Jefferson City Dolomites

Diabase dikes and sills (Precambrian Y) at surface, covers < 0.1 % of this area

Diabase dikes and sills.

Alluvium (Holocene to Pleistocene) at surface, covers < 0.1 % of this area

unconsolidated sand, silt, clay, and gravel

Alluvium - Alluvial deposits of local streams or of overbank flow of major streams (Holocene) at surface, covers < 0.1 % of this area

Alluvial deposits of local streams or of overbank flow of major streams - In some areas includes deposits in abandoned meanders of major streams

Terrace deposits (Late Pleistocene) at surface, covers < 0.1 % of this area

Alluvial deposits on one or more terrace levels

Kimmswick (Trenton) Limestone and Decorah Formation (Upper Ordovician (Stage 6)) at surface, covers < 0.1 % of this area

Kimmswick (Trenton) Limestone and Decorah Formation in southern and western Illinois.

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone (Mississippian (Tourniaisian to Visean)) at surface, covers < 0.1 % of this area

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone.

Boone Formation (Early Mississippian- Meramecian to Osagean) at surface, covers < 0.1 % of this area

Boone Formation

Ancell Group (Middle Ordovician (Darriwillian) to Upper Ordovician (Stage 5)) at surface, covers < 0.1 % of this area

Ancell Group, includes St. Peter Sandstone, Dutchtown Limestone, Joachim Dolomite, and Glenwood Formation; includes Prairie du Chien Group in Jo Daviess County of northwestern Illinois.

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

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.

Keokuk and Reeds Spring Formations and St. Joe Group (Early Mississippian) at surface, covers < 0.1 % of this area

TULSA- "Keokuk Formation," chert and limestone. "Reeds Spring Formation," chert and limestone. "St. Joe Group," limestone and shale. FORT SMITH- Mkr "Keokuk Formation," chert; "Reeds Spring Formation," chert and limestone; and "St. Joe 'Group,'" limestone and marlstone.

St. Louis Limestone (Mississippian (Visean)) at surface, covers < 0.1 % of this area

St. Louis Limestone.

Wabaunsee Group (Upper Pennsylvanian, middle-upper Virgilian) at surface, covers < 0.1 % of this area

Interval includes Howard, White Cloud, Scranton, Bern, Auburn, Emporia, Willard, Zeandale, Pillsbury, Stotler, Root formations. Primary Lithologies: shale, light to dark gray; mudstone, gray, part laminated silty to sandy. Secondary Lithologies: limestone, fossiliferous, part coated grain/Osagia; pedogenic mudstone, part red to maroon, part calcareous/nodular; siltstone to very fine sandstone. Minor: black shale; coal. Maximum thickness 320 ft (98 m) in Fremont County.

Augusta Group (Middle Mississippian, Osagean) at surface, covers < 0.1 % of this area

Interval includes Burlington, Keokuk, and Warsaw formations. Upper Warsaw strata locally preserved at top of interval in extreme southeast Iowa are lower Meramecian age . Primary Lithologies: dolomite, part argillaceous to shaly; dolomitic limestone, fossiliferous; fossiliferous limestone (especially crinoidal packstone-grainstone). Secondary Lithologies: glauconitic limestone/dolomite; shale, gray to green-gray, part dolomitic, part silty; chert, nodular to bedded. Minor: quartz crystals, quartz geodes, chalcedony; phosphatic dolomite/limestone (“bone bed”); siltstone, dolomitic. Lithologies noted only in northern Iowa: oolitic limestone; “sublithographic” limestone; dolomite/chert breccia. Interval is erosionally beveled beneath sub-“St. Louis” and sub-Pennsylvanian unconformities. Maximum thicknesses in northern Iowa: 85-105 ft (26-32 m). Maximum thicknesses in southern Iowa: 155-240 ft (47-73 m).

Maquoketa Formation or Group (Upper Ordovician (Stage 6 to Hirnatian)) at surface, covers < 0.1 % of this area

Maquoketa Formation or Group, includes Cape Limestone, Cape La Croix Shale, Thebes Sandstone, Orchard Creek Shale, Girardeau Limestone, and Leemon Formation in southern Illinois; includes Scales Shale, Fort Atkinson Limestone, Brainard Shale, and Neda Formation in northern Illinois; includes Noix Oolite in western Illinois.

Platteville Group (Upper Ordovician (Stage 5)) at surface, covers < 0.1 % of this area

Platteville Group, includes Pecatonica, Mifflin, Grand Detour, Nachusa, and Quimbys Mill Formations; includes Plattin Limestone in southwestern Illinois.

Lower Cherokee Group and Raccoon Creek Group (Lower-Middle Pennsylvanian; Morrowan-lower Desmoinesian) at surface, covers < 0.1 % of this area

Lower Cherokee Group in southern, central, and western Iowa includes Kilbourn, Kalo, Floris formations (primarily Atokan-lower Desmoinesian, locally Morrowan at base); Raccoon Creek Group in eastern Iowa includes “Caseyville” and Tradewater formations (primarily Morrowan at most localities; locally includes Atokan-lower Desmoinesian Tradewater Formation in upper part). Primary Lithologies: shale/mudstone, light to dark gray, part silty to sandy; sandstone, very fine to medium grained; siltstone, gray. Secondary Lithologies: carbonaceous shale/mudstone, gray to black; phosphatic black shale; limestone, dense, part fossiliferous, part sandy; coal (beds locally > 2 ft). Minor: sandstone, coarse-grained to granular, part conglomeratic; mudstone, red to pink; limestone concretions (may be septarian); cone-in-cone limestone; siderite/ironstone concretions and pellets; pyrite. Maximum thicknesses Raccoon Creek Group in Muscatine-Scott counties: 230-250 ft (70-75 m). Maximum thicknesses Lower Cherokee Group across outcrop belt: 200-370 ft (60-113 m). Maximum thickness in southwest Iowa subsurface: 650 ft (200 m).

Lower Pope Group (Aux Vases Sandstone through Glen Dean Limestone) (Mississippian (Visean)) at surface, covers < 0.1 % of this area

Lower Pope Group (Aux Vases Sandstone through Glen Dean Limestone).

Marmaton Group (Early Pennsylvanian- Desmoinesian) at surface, covers < 0.1 % of this area

Includes: Lost Branch FM, Memorial Shale, Lenapah Limestone (base LE), Nowata Shale, Altamont Limestone (base PA), Bandera Shale, Pawnee Limestone (base PA), Labette Shale and Fort Scott Limestone.

Marmaton Group (Middle Pennsylvanian, upper Desmoinesian) at surface, covers < 0.1 % of this area

Interval includes Morgan School, Mouse Creek, Labette, Pawnee, Bandera, Altamont, Nowata, Lenapah, Memorial, Lost Branch formations. Primary Lithologies: shale/mudstone, light to dark gray; limestone, fossiliferous. Secondary Lithologies: mudstone, green-gray to red/maroon; shale, black, phosphatic; sandstone, very fine to medium grained. Minor: coal; siltstone, conglomerate. Maximum thicknesses: 125-175 ft (38-52 m).

Dune sand (Late Pleistocene) at surface, covers < 0.1 % of this area

Deposited mostly on terrace deposits of the second level. Younger than some terrace deposits, older than others

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone (Middle Devonian (Givetian) to Upper Devonian (Fammenian)) at surface, covers < 0.1 % of this area

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone.

Clayton Formation, Porters Creek Formation, Claiborne Formation, Wilcox Formation (Tertiary (Paleocene) to Tertiary (Pliocene)) at surface, covers < 0.1 % of this area

Clayton and Porters Creek Formations; Claiborne and Wilcox Formations.

Wabaunsee Group (Late Pennsylvanian - Virgilian) at surface, covers < 0.1 % of this area

Shale, sandstone, and interbedded limestone. Shale is light gray to dark gray, greenish gray, red, or black; contains very thin layers of siltstone; locally very fossiliferous, carbonaceous. Sandstone is brownish gray to yellowish gray, or gray, argillaceous , and micaceous. Limestone is dark gray to medium gray, yellowish gray, thin bedded to thick bedded; very fossiliferous. Contains coal beds less than 1 ft. thick. Approx. max thickness 300 ft

Warsaw Formation and Salem Limestone (Mississippian (Visean)) at surface, covers < 0.1 % of this area

Warsaw Formation and Salem Limestone in western Illinois.

Tamms Group (Upper Silurian (Pridoli) to Lower Devonian (Emsian)) at surface, covers < 0.1 % of this area

Tamms Group, includes Bailey Limestone, “Flat Gap Limestone”, Grassy Knob Chert, Backbone Limestone, and Clear Creek Formation.

Glen Park Formation, Hannibal Shale, Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone (Mississippian (Tourniaisian)) at surface, covers < 0.1 % of this area

Glen Park Formation, Hannibal Shale, Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone.

Pleasanton Group (Middle Pennsylvanian- Missourian) at surface, covers < 0.1 % of this area

Includes: Shale Hill FM (base SH), and Hepler FM. Chiefly gray to very dark gray or yellowish gray shale with sandstone members and some limestone and coal.

Silurian System undivided (Silurian (Llandovery to Pridoli)) at surface, covers < 0.1 % of this area

Silurian System undivided, includes Sexton Creek Limestone, St. Clair Limestone, and Moccasin Springs Formation in southern Illinois; includes Wilhelmi Formation, Elwood Dolomite, Kankakee Dolomite, Joliet Dolomite, Sugar Run Dolomite, and Racine Dolomite in northeastern Illinois; includes Mosalem, Tete des Morts, Blanding, Sweeney, Marcus, and Racine Dolomites in northwestern Illinois.

Kansas City Group (Middle Pennsylvanian- Missourian) at surface, covers < 0.1 % of this area

Includes: Lane Shale,Wyandotte Limestone (base WY), Liberty Memorial Shale, Iola Limestone (base I), Chanute Shale (base CH), Dewey Limestone, Nellie Bly FM, Cherryvale FM, Dennis Limestone (base DN), Galeburg Shale, Mound Valley Limestone, Ladore Shale, Swope Limestone (base SW), Elm Branch Shale, Hertha Limestone.

Ste. Genevieve Limestone (Mississippian (Visean)) at surface, covers < 0.1 % of this area

Ste. Genevieve Limestone.

Meramecian and Osagian Series: Warsaw Limestone and Keokuk Limestone (Mississippian- Osagian) at surface, covers < 0.1 % of this area

Warsaw Limestone- semigranular limestone interlaminated with saccharoidal dolomite with large amounts of gray chert; glauconite occurrs in the lower part. Keokuk Limestone- white tripolitic, chert, siliceous limestone, and dolomite

Douglas Group (Late Pennsylvanian- Virgilian) at surface, covers < 0.1 % of this area

Lawrence FM (base LA)- mostly gray shale and sandstone with minor red shale, coal, gray limestone and conglomerate, thickness ranges from 140ft to 250 ft. Stranger FM- five members containing sandstone, shale, and minor limestone, coal and conglomerate ranging from 100 ft. to 180 ft. thickness.

Alluvium (Pleistocene to Holocene) at surface, covers < 0.1 % of this area

Alluvium; includes glacial deposits along the Ohio River and its tributaries west of Cannelton locks

Kinderhookian formations (Lower Mississippian, Kinderhookian) at surface, covers < 0.1 % of this area

Interval includes Prospect Hill, Chapin, Maynes Creek, and Wassonville formations; locally includes basal Crapo (“McCraney”) Formation in southeastern Iowa. Primary Lithologies: dolomite, part cherty to very cherty, part fossiliferous (Maynes Creek-Wassonville formations); limestone, skeletal to oolitic (Chapin Fm; lower Wassonville Fm/Starrs Cave Member; middle Maynes Creek/“Eagle City” member; basal Crapo Fm); siltstone (Prospect Hill Fm). Secondary Lithologies: shale, gray, silty (Prospect Hill Fm of southeastern Iowa); limestone, dense, “sublithographic” to stromatolitic (upper Maynes Creek Fm); limestone and dolomite, dense, nodular to banded, part silty (Crapo Fm). Maximum thicknesses for total interval: 100-175 ft (30-53 m). Thickness variations: Crapo (“McCraney”) Fm, 0-65 ft (20 m); Prospect Hill Fm, 0-90 ft (27 m), generally < 25 ft (8 m); Chapin Fm, 0-30 ft (9 m), generally < 10 ft (3 m); Maynes Creek Fm, 35-155 ft (11-47 m), thickest in central to northern Iowa; Wassonville Fm (southeast Iowa only), 0-70 ft (21 m), replaced to northwest by Maynes Creek and Chapin formations, beveled beneath sub-Burlington unconformity to southeast.

Shawnee Group (Upper Pennsylvanian, lower-middle Virgilian) at surface, covers < 0.1 % of this area

Interval includes Oread, Kanwaka, Lecompton, Tecumseh, Deer Creek, Calhoun, Topeka formations. Primary Lithologies: limestone, fossiliferous, part coated grain/Osagia; shale/mudstone, light to dark gray. Secondary Lithologies: pedogenic mudstone, part calcareous/nodular; siltstone to very fine sandstone; black shale, phosphatic. Minor: chert; coal, coaly shale; red-brown mudstone. Maximum thicknesses 190-220 ft (58-67 m).

Alluvium and terrace deposits (Holocene to Pleistocene) at surface, covers < 0.1 % of this area

Alluvial deposits of present streams and on one or more terrace levels

Powell Dolomite (Early Ordovician) at surface, covers < 0.1 % of this area

Powell Dolomite

Chattanooga Shale (Lower Mississippian and Upper Devonian), Clifty Limestone (Middle Devonian), and Penters Chert (Lower Devonian) (Early Mississippian to Early Devonian) at surface, covers < 0.1 % of this area

Chattanooga Shale (Lower Mississippian and Upper Devonian), Clifty Limestone (Middle Devonian), and Penters Chert (Lower Devonian)

Famennian formations (Upper Devonian, lower to upper Famennian) at surface, covers < 0.1 % of this area

Interval includes Grassy Creek Shale, Saverton Shale, “Maple Mill” Shale, English River Formation, Louisiana Limestone (Lee County only), Aplington Formation (northern and western Iowa only), Sheffield Shale (central and northern Iowa). Famennian strata onlap Lime Creek Fm to the northwest. Primary Lithologies: shale, gray to green-gray, part silty; siltstone (especially English River Fm). Secondary Lithologies: shale, olive-brown and medium to dark brown, part laminated (Grassy Creek Fm, southeast Iowa); dolomite, part fossiliferous, part cherty, part argillaceous (Aplington Fm). Minor: interstratified dolomite and limestone, part fossiliferous (Louisiana Limestone); ooidal ironstone and phosphorite; phosphatic siltstone (“bone bed”); shale, red-brown. Maximum thicknesses in outcrop belt: southeast Iowa, 135-310 ft (41-95 m), thickest in Washington, Louisa, Des Moines counties; northern and central Iowa, 25-135 ft (8-41 m).

Sand and clay (Cretaceous) at surface, covers < 0.1 % of this area

Sand and clay

Silt and sand (Early Pleistocene) at surface, covers < 0.1 % of this area

Contains lenses of gravel and clay

Muscatatuck Group (Middle Devonian (Eifelian to Givetian)) at surface, covers < 0.1 % of this area

Muscatatuck Group, includes Grand Tower Limestone and St. Laurent (Alto and Lingle) Formation in southern Illinois; includes Detroit River Formation, Wapsipinicon Limestone, and Cedar Valley Limestone in northern and western Illinois.

St. Louis and Pella Formations (Middle-Upper Mississippian, Meramecian-lower Chesterian) at surface, covers < 0.1 % of this area

Interval includes lower “St. Louis” (Meramecian) Croton and Yenruogis members; upper “St. Louis” (lower Genevievian) Verdi and Waugh members (interval does not correlate with type St. Louis of Missouri); Pella Fm (upper Genevievian); base includes Sonora Fm (Meramecian) in parts of southeast Iowa (Lee, Van Buren, Henry, Des Moines, Jefferson counties). Primary Lithologies: dolomite, part silty/sandy, part fossiliferous; limestone, part sandy to fossiliferous; part “sublithographic,” part argillaceous. Secondary Lithologies: dolomite/limestone breccia; shale/marl, green-gray, calcareous; sandstone, fine to medium-grained; siltstone; gypsum/anhydrite (south-central Iowa). Minor: limestone, oolitic; shale, gray; shale, red to pink; chert/chalcedony. Croton Member contains gypsum-anhydrite in subsurface outside of outcrop belt. Interval is erosionally beveled to locally absent beneath Pcl; Pella Formation absent over broader areas. Maximum thicknesses for total interval 60-150 ft (18-45 m); maximum thickness Pella Formation 75 ft (23 m); maximum thickness “St. Louis” Formation 75 ft (23 m); maximum thickness Sonora Formation 35 ft (11 m).

Alluvium (Holocene) at surface, covers < 0.1 % of this area

WOODWARD- Lenticular and interfingering deposits of gravel, sand, silt, and clay. Generally light-tan to gray. Thickness along major streams ranges up to 100 feet and probably averages 40 feet; along minor streams the thickness ranges up to 45 feet and probably averages 20 feet. ENID- Sand, silt, clay, and locally gravel. Maximum thickness ranges from 30 to 80 feet (9 to 24 m) along major streams and from 0 to 60 feet (0 to 18 m) along minor streams. TULSA- Gravel, sand, silt, and clay. TULSA- Gravel, sand, silt, and clay. OKLAHOMA CITY- Sand, silt, clay, and lenticular beds of gravel. Thickness ranges from about 30 to 100 feet and probably averages about 50 feet along major streams. Along minor streams, thickness ranges from a few feet to about 50 feet and probably averages about 25 feet. LAWTON- Sand, clay, and gravel as much as 50 feet (15 m) thick; Shown only along major streams and tributaries. ARDMORE-SHERMAN- Gravel, sand, silt, and clay, including low terraces; thickness, about 25 to 100 feet. McALESTER TEXARKANA- Gravel, sand, silt, and clay, including low terraces about 30 feet above channels; thickness, about 50 feet along Little River and 110 feet along Red River.

Pitkin Limestone, Fayetteville Shale (including the Wedington Sandstone member), and Batesville Sandstone (including the Hindsville Limestone Member) (Late Mississippian- Chesterian) at surface, covers < 0.1 % of this area

Pitkin Limestone, Fayetteville Shale (including the Wedington Sandstone member), and Batesville Sandstone (including the Hindsville Limestone Member)

Pitkin + Fayetteville + Batesville + Hindsville + Moorefield Formations (Late Mississippian) at surface, covers < 0.1 % of this area

TULSA- "Pitkin Formation," limestone. "Fayetteville Formation," shale and thin limestone. "Batesville Formation," fine-grained sandstone. "Hindsville Formation," limestone and shale. "Moorefield Formation," limestone, shale, and siltstone.

Cherokee Group (Early Pennsylvanian- Desmoinesian) at surface, covers < 0.1 % of this area

Includes: Cabaniss FM (base CA) with Verdigris Limestone Member (base V) and Mineral coal bed (base MC), Krebs FM with Bluejacket Sandstone Member (base BJ) and Warner Sandstone Member (base WR).

Upper Pope Group (Tar Springs Sandstone through Kinkaid Limestone) (Mississippian (Serpukhovian)) at surface, covers < 0.1 % of this area

Upper Pope Group (Tar Springs Sandstone through Kinkaid Limestone).

Loess (Holocene to Pleistocene) at surface, covers < 0.1 % of this area

eolian silts

Bronson Group (Middle to Upper Pennsylvanian, uppermost Desmoinesian-lower Missourian) at surface, covers < 0.1 % of this area

Interval includes Pleasanton, Hertha, Elm Branch, Swope, Galesburg, Dennis formations. Primary Lithologies: limestone, fossiliferous; shale/mudstone, light to dark gray. Secondary lithologies: mudstone to siltstone, gray to green-gray; limestone, coated grain. Minor: black shale, phosphatic; red/maroon mudstone; coal; chert. Maximum thicknesses 100-130 ft (30-40 m).

Douglas Group (Upper Pennsylvanian, upper Missourian-lower Virgilian) at surface, covers < 0.1 % of this area

Interval includes Stranger, Cass, Lawrence formations. Primary Lithologies: shale and mudstone, light to dark gray, part silt laminated. Secondary Lithologies: limestone, fossiliferous, part coated grain; siltstone to very fine sandstone; pedogenic mudstone, part red-brown, part calcareous/nodular. Minor: coal, carbonaceous shale; black shale. Maximum thicknesses 90-135 ft (27-41 m).