Ogallala Formation (Pliocene to Miocene) at surface, covers 14 % of this area
Playa deposits (Pleistocene and Holocene) at surface, covers 2 % of this area
Quartermaster Formation (Permian; Guadalupe Series) at surface, covers 1 % of this area
Quartermaster Formation; North and central Texas including panhandle.
Alluvium (Holocene) at surface, covers 0.7 % of this area