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Geologic units in Gillespie county, Texas

Edwards Limestone (Early Cretaceous) at surface, covers 46 % of this area

Edwards Limestone

Hensell Sand (Early Cretaceous; Comanchean Series) at surface, covers 22 % of this area

Hensell Sand

Glen Rose Limestone (Early Cretaceous) at surface, covers 17 % of this area

Glen Rose Limestone

Town Mountain Granite (preCambrian (Proterozoic)) at surface, covers 3 % of this area

Town Mountain Granite

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

Alluvium

Hickory Sandstone Member (Middle Cambrian) at surface, covers 1 % of this area

Hickory Sandstone Member

Big Branch Gneiss (preCambrian (Proterozoic)) at surface, covers 1 % of this area

Big Branch Gneiss

Tanyard Formation (Early Ordovician) at surface, covers 1 % of this area

Tanyard Formation

Packsaddle Schist (preCambrian (Proterozoic); Llano Series) at surface, covers 1 % of this area

Packsaddle Schist

Riley Formation showing Lion Mountain Sandstone and Cap Mountain Limestone Members, undivided (Middle Cambrian) at surface, covers 1 % of this area

Riley Formation showing Lion Mountain Sandstone and Cap Mountain Limestone Members, undivided

Valley Spring Gneiss (preCambrian (Proterozoic)) at surface, covers 0.8 % of this area

Valley Spring Gneiss

Wilberns Formation showing Point Peak, Morgan Creek Limestone, and Welge Sandstone Members, undivided (Late Cambrian) at surface, covers 0.8 % of this area

Wilberns Formation showing Point Peak, Morgan Creek Limestone, and Welge Sandstone Members, undivided

Quaternary deposit, undivided (Quaternary) at surface, covers 0.6 % of this area

Quaternary deposit, undivided

Sparta Sand (Eocene) at surface, covers 0.3 % of this area

Sparta Sand

Wilberns Formation showing San Saba Member (Late Cambrian) at surface, covers 0.3 % of this area

Wilberns Formation showing San Saba Member

Gorman Formation (Early Ordovician) at surface, covers 0.2 % of this area

Gorman Formation

Caliche deposits (Pleistocene and Holocene) at surface, covers 0.2 % of this area

Caliche deposits

Mafic igneous rocks (preCambrian (Proterozoic)) at surface, covers 0.2 % of this area

Mafic igneous rocks

Coal Creek Serpentinite (preCambrian (Proterozoic)) at surface, covers 0.2 % of this area

Coal Creek Serpentinite

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

Terrace deposits

High gravel deposits (Pleistocene) at surface, covers < 0.1 % of this area

High gravel deposits

Younger granitic intrusion (preCambrian (Proterozoic)) at surface, covers < 0.1 % of this area

Younger granitic intrusion