Geologic units in Castro county, Texas

Blackwater Draw Formation (Pleistocene) at surface, covers 93 % of this area

Blackwater Draw Formation

Ogallala Formation (Pliocene to Miocene) at surface, covers 4 % of this area

Ogallala Formation

Playa deposits (Pleistocene and Holocene) at surface, covers 2 % of this area

Playa deposits

Sand dune deposits (Holocene) at surface, covers 0.4 % of this area

Sand dune deposits