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Geologic units in Callahan county, Texas

Antlers Sand (Phanerozoic | Mesozoic | Cretaceous-Early) at surface, covers 31 % of this area

Antlers Sand

Santa Anna Branch Shale (Phanerozoic | Paleozoic | Permian [Wolfcamp]) at surface, covers 13 % of this area

Santa Anna Branch Shale

Admiral Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp]) at surface, covers 12 % of this area

Admiral Formation

Grape Creek Formation (Phanerozoic | Paleozoic | Permian [Leonard]) at surface, covers 8 % of this area

Grape Creek Formation

Lithology: shale; limestone

Sedwick Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp]) at surface, covers 8 % of this area

Sedwick Formation

Coleman Junction Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp]) at surface, covers 7 % of this area

Coleman Junction Formation

alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 6 % of this area

alluvium

Lithology: sand; silt; clay or mud; gravel

Elm Creek Formation (Phanerozoic | Paleozoic | Permian [Leonard]) at surface, covers 5 % of this area

Elm Creek Formation

Lithology: shale; mudstone; limestone

Talpa Formation (Phanerozoic | Paleozoic | Permian [Leonard]) at surface, covers 4 % of this area

Talpa Formation

Lithology: shale; limestone

Edwards Limestone (Phanerozoic | Mesozoic | Cretaceous-Early) at surface, covers 3 % of this area

Edwards Limestone

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

sand, silt, clay, and gravel. locally indurated with calcium carbonate (caliche); includes point bar, natural levee, stream channel, sand dune, terrace, alluvial fan, landslide bolson and playa deposits

Jagger Bend and Valera Formations, undivided (Phanerozoic | Paleozoic | Permian [Leonard]) at surface, covers 0.9 % of this area

Jagger Bend and Valera Formations, undivided

Lithology: shale; mudstone; limestone

Comanche Peak Limestone and Walnut Clay, undivided (Phanerozoic | Mesozoic | Cretaceous-Early) at surface, covers 0.9 % of this area

Comanche Peak Limestone and Walnut Clay, undivided

Pueblo Formation (Phanerozoic | Paleozoic | Permian [Wolfcamp]) at surface, covers 0.2 % of this area

Pueblo Formation

Lithology: mudstone; sandstone

Terrace deposits (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers < 0.1 % of this area

Terrace deposits

playa deposits (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers < 0.1 % of this area

playa deposits

Lithology: clay or mud; silt