Geologic units in Roberts county, Texas

Ogallala Formation (Pliocene to Miocene) at surface, covers 78 % of this area

Ogallala Formation

Blackwater Draw Formation (Pleistocene) at surface, covers 10 % of this area

Blackwater Draw Formation

Alluvium (Holocene) at surface, covers 6 % of this area

Alluvium

Quaternary deposit, undivided (Quaternary) at surface, covers 4 % of this area

Quaternary deposit, undivided

Dune sand sheet deposits (Holocene) at surface, covers 2 % of this area

Dune sand sheet deposits

Terrace deposits (Pleistocene and Holocene) at surface, covers 0.6 % of this area

Terrace deposits

Playa deposits (Pleistocene and Holocene) at surface, covers < 0.1 % of this area

Playa deposits

Sand sheet deposits (Holocene) at surface, covers < 0.1 % of this area

Sand sheet deposits