Geologic units in Washington county, Kansas

Dakota Formation (Early Cretaceous) at surface, covers 51 % of this area

White, gray, red, brown and tan kaolinitic claystone, mudstone, shale and siltstone interbedded with grayish to yellowish brown thick lenticular sandstone beds. It also contains lignite and sandstone is commonly well cemented with iron oxide and calcite.

Sumner Group (Late Permian - Cimarronian) at surface, covers 13 % of this area

Ninnescah Shale (base N)- mostly red silty shale with some gray shale , argillaceous limestone and dolomite. Wellington FM with Carlton Limestone Member (base CR)-mostly gray and some red shale with minor limestone and dolomite, siltstone, gypsum and anhydrite

Chase Group (Early Permian - Gearyan) at surface, covers 11 % of this area

Nolans Limestone- upper and lower limestone seperated by shale, 40 ft thick. Odell Shale- mostly red and green shale, 40 ft. thick. Winfield Limestone (base WF)- cherty limestone with fossiliferous gray shale, 25 ft. thick. Doyle Shale- two shale members seperated limestone, 70 ft. thick. Barneston Limestone (base BA)- two thick limestone members seperated by thin limestone, 90 ft. thick: with Fort Riley Limestone Member( base FR)- gray to tan massive to thin bedded limestone with minor gray shale, 45 ft thick. Matfeild Shale- two varicolored shale members seperated by limestone, 80 ft. thick. Wreford Limestone- two cherty limestone members seperated shale, 40 ft. thick.

Loess (Holocene to Pleistocene) at surface, covers 9 % of this area

eolian silts

Greenhorn Limestone and Graneros Shale (Late Cretaceous) at surface, covers 6 % of this area

Greenhorn FM- thin bedded gray, chalky limestone and calcareous shale. Graneros Shale- fissile, noncalcareous, gray shale locally contains sandstone and siltstone beds.

Alluvium (Holocene to Pleistocene) at surface, covers 5 % of this area

unconsolidated sand, silt, clay, and gravel

Alluvium (Pleistocene) at surface, covers 3 % of this area

unconsolidated sand, silt, clay, and gravel

Drift (Pleistocene) at surface, covers 3 % of this area

sand, silt, clay, and some gravel

Greenhorn Limestone and Graneros Shale (Late Cretaceous) at surface, covers 0.1 % of this area

Greenhorn Limestone- medium- to light-gray limestone interbedded with argillaceous limestone, marl and calcareous shale; contains Inoceramus fossils. Upper and lower contacts gradational. Approx. max thickness 30 ft. Graneros Shale- medium- to dark-gray, partly calcareous shale. Interbeds of siltstone, sandstone, and carbonaceous shale, and thin bentonite layers in upper part. Approx. max thickness 60 ft.

Dakota Group (Early Cretaceous) at surface, covers < 0.1 % 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.

Kiowa Shale and Cheyenne Sandstone (Early Cretaceous) at surface, covers < 0.1 % of this area

Kiowa Shale or FM- light -gray to black illitic shale with thin coquinoidal limestone beds at the base; sandstone lenses common. Cheyenne Sandstone- massive to crossbedded, light-gray to buff fine-grained sandstone with lenses of gray sandy shale and conglomerate.

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

unconsolidated dune sand

Chase Group (Permian) at surface, covers < 0.1 % of this area

Limestone and shale. Limestone is light gray to dark gray, yellowish gray to pale yellowish brown. Two limestones in the upper part are thin bedded to medium bedded, argillaceous, cherty and fossiliferous; two limestones in the lower part are medium to massive bedded, very cherty, and fossiliferous. Shale is gray, green, red, redish brown, calcareous, arenaceous, fossiliferous; locally fissile. Approx. max thickness 300 ft.