Geologic units in Mason county, Texas

Hickory Sandstone Member (Middle Cambrian) at surface, covers 13 % of this area

Hickory Sandstone Member

Valley Spring Gneiss (preCambrian (Proterozoic)) at surface, covers 11 % of this area

Valley Spring Gneiss

Packsaddle Schist (preCambrian (Proterozoic); Llano Series) at surface, covers 9 % of this area

Packsaddle Schist

Hensell Sand (Early Cretaceous; Comanchean Series) at surface, covers 9 % of this area

Hensell Sand

Riley Formation showing Lion Mountain Sandstone and Cap Mountain Limestone Members, undivided (Middle Cambrian) at surface, covers 8 % of this area

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

Tanyard Formation (Early Ordovician) at surface, covers 8 % of this area

Tanyard Formation

Town Mountain Granite (preCambrian (Proterozoic)) at surface, covers 7 % of this area

Town Mountain Granite

Edwards Limestone (Early Cretaceous) at surface, covers 7 % of this area

Edwards Limestone

Wilberns Formation showing Point Peak, Morgan Creek Limestone, and Welge Sandstone Members, undivided (Late Cambrian) at surface, covers 7 % of this area

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

Sparta Sand (Eocene) at surface, covers 5 % of this area

Sparta Sand

Gorman Formation (Early Ordovician) at surface, covers 4 % of this area

Gorman Formation

Lost Creek Gneiss (preCambrian (Proterozoic)) at surface, covers 4 % of this area

Lost Creek Gneiss

Younger granitic intrusion (preCambrian (Proterozoic)) at surface, covers 3 % of this area

Younger granitic intrusion

Wilberns Formation showing San Saba Member (Late Cambrian) at surface, covers 2 % of this area

Wilberns Formation showing San Saba Member

Marble Falls Limestone (Pennsylvanian; Morrow Series) at surface, covers 0.6 % of this area

Marble Falls Limestone

Alluvium (Holocene) at surface, covers 0.4 % of this area

Alluvium

Barnett Formation, Chappel Limestone, Houy, Zesch, Bear Spring, and Stribling Formations, and Pillar Bluff Limestone, undivided (Late; Middle; and Early Mississippian and Devonian) at surface, covers 0.3 % of this area

Barnett Formation, Chappel Limestone, Houy, Zesch, Bear Spring, and Stribling Formations, and Pillar Bluff Limestone, undivided

Smithwick Formation (Middle Pennsylvanian; Atoka Series) at surface, covers 0.2 % of this area

Smithwick Formation

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

Terrace deposits

Canyon Group, undivided (Late Pennsylvanian; Missouri Series) at surface, covers < 0.1 % of this area

Canyon Group, undivided

Quaternary deposit, undivided (Quaternary) at surface, covers < 0.1 % of this area

Quaternary deposit, undivided

Antlers Sand (Early Cretaceous) at surface, covers < 0.1 % of this area

Antlers Sand

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

Caliche deposits