Geologic units in Zavala county, Texas

El Pico Clay (Eocene) at surface, covers 22 % of this area

El Pico Clay

Leona Formation (Pleistocene) at surface, covers 16 % of this area

Leona Formation

Bigford Formation (Eocene) at surface, covers 15 % of this area

Bigford Formation

Laredo Formation (Middle Eocene) at surface, covers 13 % of this area

Laredo Formation

Terrace deposits (Pleistocene and Holocene) at surface, covers 9 % of this area

Terrace deposits

Alluvium (Holocene) at surface, covers 8 % of this area

Alluvium

Carizzo Sand (Eocene) at surface, covers 7 % of this area

Carizzo Sand

Uvalde Gravel (Pliocene to Pleistocene) at surface, covers 4 % of this area

Uvalde Gravel

Indio Formation (Paleocene to Eocene) at surface, covers 4 % of this area

Indio Formation

Quaternary deposit, undivided (Quaternary) at surface, covers 1 % of this area

Quaternary deposit, undivided

Escondido Formation (Late Cretaceous; Gulfian Series) at surface, covers 0.3 % of this area

Escondido Formation

Kincaid Formation (Paleocene) at surface, covers 0.1 % of this area

Kincaid Formation

Igneous rocks of Austin age (Late Cretaceous) at surface, covers < 0.1 % of this area

Igneous rocks of Austin age