Geologic units in Brown county, Texas

Strawn Group (Middle Pennsylvanian; Atoka and Des Moines Series) at surface, covers 17 % of this area

Strawn Group

Thrifty and Graham Formations, undivided (Late Pennsylvanian; Virgil Series) at surface, covers 17 % of this area

Thrifty and Graham Formations, undivided

Travis Peak Formation (Early Cretaceous) at surface, covers 10 % of this area

Travis Peak Formation

Harpersville Formation (Pennsylvanian; Virgil Series) at surface, covers 6 % of this area

Harpersville Formation

Glen Rose Limestone (Early Cretaceous) at surface, covers 6 % of this area

Glen Rose Limestone

Antlers Sand (Early Cretaceous) at surface, covers 5 % of this area

Antlers Sand

Winchell Limestone (Pennsylvanian; Missouri Series) at surface, covers 4 % of this area

Winchell Limestone

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

Alluvium

Ranger Limestone and Placid Creek Shale, undivided (Pennsylvanian; Missouri Series) at surface, covers 4 % of this area

Ranger Limestone and Placid Creek Shale, undivided

Cedarton Shale and Adams Branch Limestone, undivided (Pennsylvanian; Missouri Series) at surface, covers 4 % of this area

Cedarton Shale and Adams Branch Limestone, undivided

Twin Mountains Formation (Early Cretaceous) at surface, covers 3 % of this area

Twin Mountains Formation

Home Creek Limestone and Colony Creek Shale, undivided (Pennsylvanian; Missouri Series) at surface, covers 3 % of this area

Home Creek Limestone and Colony Creek Shale, undivided

Paluxy Sand (Early Cretaceous) at surface, covers 3 % of this area

Paluxy Sand

Pueblo Formation (Permian; Wolfcamp Series) at surface, covers 3 % of this area

Pueblo Formation

Comanche Peak Limestone and Walnut Clay, undivided (Early Cretaceous) at surface, covers 2 % of this area

Comanche Peak Limestone and Walnut Clay, undivided

Walnut Clay (Early Cretaceous) at surface, covers 2 % of this area

Walnut Clay

Moran Formation (Permian; Wolfcamp Series) at surface, covers 1 % of this area

Moran Formation

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

Quaternary deposit, undivided

Terrace deposits (Pleistocene and Holocene) at surface, covers 1.0 % of this area

Terrace deposits

Edwards Limestone (Early Cretaceous) at surface, covers 0.7 % of this area

Edwards Limestone

High gravel deposits (Pleistocene) at surface, covers 0.3 % of this area

High gravel deposits

Undivided part Fredericksberg Group (Early Cretaceous) at surface, covers 0.2 % of this area

Undivided part Fredericksberg Group

Santa Anna Branch Shale and Sedwick and Moran Formations, undivided (Permian; Wolfcamp Series) at surface, covers < 0.1 % of this area

Santa Anna Branch Shale and Sedwick and Moran Formations, undivided