Walnut Clay
(Early Cretaceous) at surface, covers 21 % of this area Walnut Clay
Glen Rose Limestone
(Early Cretaceous) at surface, covers 11 % of this area Glen Rose Limestone
Tanyard Formation
(Early Ordovician) at surface, covers 7 % of this area Tanyard Formation
Town Mountain Granite
(preCambrian (Proterozoic)) at surface, covers 5 % of this area Town Mountain Granite
Hensell Sand
(Early Cretaceous; Comanchean Series) at surface, covers 3 % of this area Hensell Sand
Honeycut Formation
(Early Ordovician) at surface, covers 3 % of this area Honeycut Formation
Gorman Formation
(Early Ordovician) at surface, covers 3 % of this area Gorman Formation
Marble Falls Limestone
(Pennsylvanian; Morrow Series) at surface, covers 3 % of this area Marble Falls Limestone
Valley Spring Gneiss
(preCambrian (Proterozoic)) at surface, covers 2 % of this area Valley Spring Gneiss
Smithwick Formation
(Middle Pennsylvanian; Atoka Series) at surface, covers 2 % of this area Smithwick Formation
Alluvium
(Holocene) at surface, covers 1 % of this area Alluvium
Terrace deposits
(Pleistocene and Holocene) at surface, covers 0.6 % of this area Terrace deposits
Packsaddle Schist
(preCambrian (Proterozoic); Llano Series) at surface, covers 0.4 % of this area Packsaddle Schist
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 0.2 % of this area Barnett Formation, Chappel Limestone, Houy, Zesch, Bear Spring, and Stribling Formations, and Pillar Bluff Limestone, undivided
