Geologic units in Osborne county, Kansas

Loess (Holocene to Pleistocene) at surface, covers 49 % of this area

eolian silts

Niobrara Chalk (Late Cretaceous) at surface, covers 22 % of this area

Interbedded, soft, light-gray calcareous shale and chalk

Carlile Shale (Late Cretaceous) at surface, covers 15 % of this area

Chalky shale with bentonite and thick chalk beds, dark gray fissile shale containing septarian concretions, and fine-grained sandstone.

Alluvium (Holocene to Pleistocene) at surface, covers 12 % of this area

unconsolidated sand, silt, clay, and gravel

Greenhorn Limestone and Graneros Shale (Late Cretaceous) at surface, covers 1 % 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.

Dakota Formation (Early Cretaceous) at surface, covers 0.7 % 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.

Ogallala Formation (Miocene) at surface, covers < 0.1 % of this area

massive to cross-bedded, generally arkosic sand, silt and gravel, locally cemented with calcium carbonate; also contains limestone, volcanic ash, diatomaceous marl, opaline sandstone and bentonitic clay