Geologic units in Callahan county, Texas

Antlers Sand (Early Cretaceous) at surface, covers 29 % of this area

Antlers Sand

Jagger Bend and Valera Formations, undivided (Permian; Leonard Series) at surface, covers 10 % of this area

Jagger Bend and Valera Formations, undivided

Admiral Formation (Permian; Wolfcamp Series) at surface, covers 9 % of this area

Admiral Formation

Bead Mountain Formation (Permian; Leonard Series) at surface, covers 8 % of this area

Bead Mountain Formation

Lueders Formation (Permian; Leonard Series) at surface, covers 7 % of this area

Lueders Formation

Santa Anna Branch Shale (Permian; Wolfcamp Series) at surface, covers 7 % of this area

Santa Anna Branch Shale

Grape Creek Formation (Permian; Leonard Series) at surface, covers 6 % of this area

Grape Creek Formation

Elm Creek Formation (Permian; Leonard Series) at surface, covers 6 % of this area

Elm Creek Formation

Sedwick Formation (Permian; Wolfcamp Series) at surface, covers 4 % of this area

Sedwick Formation

Moran Formation (Permian; Wolfcamp Series) at surface, covers 4 % of this area

Moran Formation

Coleman Junction Formation (Permian; Wolfcamp Series) at surface, covers 4 % of this area

Coleman Junction Formation

Alluvium (Holocene) at surface, covers 3 % of this area

Alluvium

Talpa Formation (Permian; Leonard Series) at surface, covers 2 % of this area

Talpa Formation

Edwards Limestone (Early Cretaceous) at surface, covers 2 % of this area

Edwards Limestone

Quaternary deposit, undivided (Quaternary) at surface, covers 0.6 % of this area

Quaternary deposit, undivided

Comanche Peak Limestone and Walnut Clay, undivided (Early Cretaceous) at surface, covers 0.4 % of this area

Comanche Peak Limestone and Walnut Clay, undivided

Pueblo Formation (Permian; Wolfcamp Series) at surface, covers < 0.1 % of this area

Pueblo Formation

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

Terrace deposits

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

Playa deposits