Geologic units in Knox county, Texas

Clear Fork Group (Permian; Leonard Series) at surface, covers 40 % of this area

Clear Fork Group

Seymour Formation (Middle Pleistocene; Irvingtonian) at surface, covers 19 % of this area

Seymour Formation

San Angelo Formation (Permian; Guadalupe Series) at surface, covers 12 % of this area

San Angelo Formation

Sand sheet deposits (Holocene) at surface, covers 9 % of this area

Sand sheet deposits

Alluvium (Holocene) at surface, covers 7 % of this area

Alluvium

Blaine Formation (Permian; Guadalupe Series) at surface, covers 5 % of this area

Blaine Formation

Terrace deposits (Pleistocene and Holocene) at surface, covers 4 % of this area

Terrace deposits

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

Dune sand sheet deposits

Quaternary deposit, undivided (Quaternary) at surface, covers 2 % of this area

Quaternary deposit, undivided

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

Playa deposits