Geologic units in Erath county, Texas

Paluxy Sand (Early Cretaceous) at surface, covers 30 % of this area

Paluxy Sand

Glen Rose Limestone (Early Cretaceous) at surface, covers 28 % of this area

Glen Rose Limestone

Twin Mountains Formation (Early Cretaceous) at surface, covers 16 % of this area

Twin Mountains Formation

Walnut Clay (Early Cretaceous) at surface, covers 13 % of this area

Walnut Clay

Mingus Formation (Pennsylvanian; Des Moines Series) at surface, covers 4 % of this area

Mingus Formation

Grindstone Creek Formation, expanded (Pennsylvanian; Des Moines Series) at surface, covers 3 % of this area

Grindstone Creek Formation, expanded

Alluvium (Holocene) at surface, covers 2 % of this area

Alluvium

Brazos River Formation (Pennsylvanian; Des Moines Series) at surface, covers 2 % of this area

Brazos River Formation

Undivided part Fredericksberg Group (Early Cretaceous) at surface, covers 1 % of this area

Undivided part Fredericksberg Group

Lazy Bend Formation (Pennsylvanian; Des Moines Series) at surface, covers 0.3 % of this area

Lazy Bend Formation

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

Terrace deposits

Undivided part of Washita Group (Early Cretaceous; Comanchean Series) at surface, covers < 0.1 % of this area

Undivided part of Washita Group