Geologic units in Zapata county, Texas

Jackson Group, undivided (Oligocene and Eocene) at surface, covers 40 % of this area

Jackson Group, undivided

Yegua Formation (Middle Eocene) at surface, covers 17 % of this area

Yegua Formation

Sand sheet deposits (Holocene) at surface, covers 16 % of this area

Sand sheet deposits

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

Laredo Formation

Catahoula Formation and Frio Clay, undivided (Oligocene) at surface, covers 4 % of this area

Catahoula Formation and Frio Clay, undivided

Alluvium (Holocene) at surface, covers 4 % of this area

Alluvium

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

Terrace deposits

Goliad Formation (Miocene) at surface, covers 0.6 % of this area

Goliad Formation

Quaternary deposit, undivided (Quaternary) at surface, covers 0.3 % of this area

Quaternary deposit, undivided

Uvalde Gravel (Pliocene to Pleistocene) at surface, covers 0.2 % of this area

Uvalde Gravel