Geologic units in Steele county, North Dakota

Additional scientific data in this geographic area

Carlile Formation (Upper Cretaceous) at surface, covers 30 % of this area

Dark-gray shale; marine offshore sediment; as thick as 120 metres (400 feet).

Pierre Formation (Upper Cretaceous) at surface, covers 30 % of this area

Dark-gray shale; marine offshore sediment; as thick as 700 metres (2,300 feet).

Greenhorn Formation (Upper Cretaceous) at surface, covers 24 % of this area

Dark-gray calcareous shale; marine offshore sediment; as thick as 45 metres (150 feet).

Niobrara Formation (Upper Cretaceous) at surface, covers 15 % of this area

Light-brown to dark-gray calcareous shale; marine offshore sediment; as thick as 75 metres (250 feet).