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Geologic units in Douglas county, Nebraska

Dakota Group (Phanerozoic | Mesozoic | Cretaceous-Early) at surface, covers 58 % 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.

Lithology: sandstone; shale; gravel

Kansas City Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Missourian]) at surface, covers 32 % 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

Lithology: limestone; shale

Marmaton Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Desmoinesian]) at surface, covers 7 % 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

Lithology: shale; limestone

Lansing Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Missourian]) at surface, covers 2 % 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

Lithology: limestone; shale

Douglas Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Virgilian]) at surface, covers 0.7 % of this area

Shale and limestone. Shale is dark gray to medium gray, red , black, fossiliferous, calcareous and locally sandy. Limestone is dark gray to light gray, thin bedded to thick bedded, fossiliferous and locally sandy. Approx. max thickness 100 ft

Lithology: shale; limestone

Shawnee Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Virgilian]) at surface, covers 0.3 % of this area

Limestone, shale and siltstone. Limestone is dark gray to very light gray, yellowish gray, very thin bedded to massive bedded, and fossiliferous; locally the thin bedds are argillaceous other beds are oolitic and a few contain chert. Shale is medium gray, greenish gray, pale red, dark redish brown, black, sandy fossiliferous and calcareous; black shale in part is fissile. Siltstone is light gray to greenish yellow, massive, calcareous; locally sandy. Approx. max thickness 200 ft

Lithology: limestone; shale; siltstone