Geologic units in Sarpy county, Nebraska

Dakota Group (Early Cretaceous) at surface, covers 43 % of this area

Upper part is white, light-gray, brownish-gray, yellow, redish-brown, and red sandstone and shale. Sandstone is very fine to coarse grained, friable, micaeous, crossbedded, and lenticular; locally contains gravel near base. contains numerous zones of ironstone and siltstone concretions of variable thickness. Middle part is light-gray, yellow, red brown and dark-gray, sandy carbonaceous shale; commonly contains a zone of concretions near top. Lower part is sandstone similar to that in upper except there are zones of siderite concretions and, locally a basal zone of chert pebbles. Approx. max thickness 600 ft.

Kansas City Group (Late Pennsylvanian - Missouria) at surface, covers 40 % of this area

Limestone and shale. Limestone is dark gray to light gray, brownish gray, very thin bedded to massive, argillaceous, fossiliferous; contains very thin layers of chert, pyrite crystals, and small flakes of mica near base. Shale is dark gray to light gray, greenish gray, red, and black; locally slighty sandy, calcareous, carbonaeous, fissile, and fossiliferous. Approx. max thickness 200 ft

Marmaton Group (Middle Pennsylvanian - Desmoinesian) at surface, covers 10 % of this area

Shale and limestone. Shale is dark gray to light gray, greenish gray, black, red, silty, sandy carbonaceous, fissile, calcareous; contains scattered limestone nodules. Limestone is medium gray to light gray, red, mottled thin bedded to thick bedded, sandy, shaly, vuggy, fossiliferous. Approx. max thickness 125 ft

Lansing Group (Late Pennsylvanian - Missourian) at surface, covers 7 % of this area

Limestone and shale. Limestone is dark gray to light gray, very thin bedded to massive, sandy fossiliferous, and cherty. Shale is dark gray to light gray, maroon, black, fossiliferous, and calcareous. Approx. max thickness 75 ft

Lansing Group (Upper Pennsylvanian, upper Missourian) at surface, covers 0.2 % of this area

Interval includes Plattsburg, Vilas, Stanton formations. Primary Lithologies: limestone, fossiliferous; shale/mudstone, light to dark gray. Secondary Lithologies: limestone, coated grain/Osagia; mudstone to siltstone, gray. Minor: black shale, phosphatic; mudstone, red-brown. Maximum thicknesses 45-78 ft (14-24 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).

Kansas City Group (Upper Pennsylvanian, middle Missourian) at surface, covers 0.1 % of this area

Interval includes Cherryvale, Nellie Bly, Dewie, Chanute, Iola, Liberty Memorial, Wyandotte, Lane formations. Primary Lithologies: limestone fossiliferous; shale/mudstone, light to dark gray. Secondary Lithologies: limestone, coated grain/Osagia. Minor: mudstone, red-brown to green-gray; siltstone; black shale, phosphatic; thin coal, carbonaceous shale. Maximum thicknesses 100-140 ft (30-43 m).

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).

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).