Geologic units in Frio county, Texas

Queen City Sand (Eocene) at surface, covers 22 % of this area

Queen City Sand

Cook Mountain Formation (Eocene) at surface, covers 17 % of this area

Cook Mountain Formation

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

Laredo Formation

Leona Formation (Pleistocene) at surface, covers 8 % of this area

Leona Formation

Uvalde Gravel (Pliocene to Pleistocene) at surface, covers 8 % of this area

Uvalde Gravel

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

Alluvium

Terrace deposits (Pleistocene and Holocene) at surface, covers 6 % of this area

Terrace deposits

El Pico Clay (Eocene) at surface, covers 5 % of this area

El Pico Clay

Reklaw Formation (Eocene) at surface, covers 4 % of this area

Reklaw Formation

Weches Formation (Eocene) at surface, covers 3 % of this area

Weches Formation

Sparta Sand (Eocene) at surface, covers 3 % of this area

Sparta Sand

Carizzo Sand (Eocene) at surface, covers 1 % of this area

Carizzo Sand

Yegua Formation (Middle Eocene) at surface, covers 0.4 % of this area

Yegua Formation

Bigford Formation (Eocene) at surface, covers 0.2 % of this area

Bigford Formation