Geologic units in Young county, Texas

Markley Formation (Pennsylvanian to Early Permian) at surface, covers 44 % of this area

Markley Formation

Thrifty and Graham Formations, undivided (Late Pennsylvanian; Virgil Series) at surface, covers 28 % of this area

Thrifty and Graham Formations, undivided

Archer City Formation (Permian; Wolfcamp Series) at surface, covers 11 % of this area

Archer City Formation

Alluvium (Holocene) at surface, covers 5 % of this area

Alluvium

Terrace deposits (Pleistocene and Holocene) at surface, covers 4 % of this area

Terrace deposits

Quaternary deposit, undivided (Quaternary) at surface, covers 2 % of this area

Quaternary deposit, undivided

Pueblo Formation (Permian; Wolfcamp Series) at surface, covers 2 % of this area

Pueblo Formation

Harpersville Formation (Pennsylvanian; Virgil Series) at surface, covers 1 % of this area

Harpersville Formation

Home Creek Limestone and Colony Creek Shale, undivided (Pennsylvanian; Missouri Series) at surface, covers 1 % of this area

Home Creek Limestone and Colony Creek Shale, undivided

Sedwick and Moran Formations, undivided (Permian; Wolfcamp Series) at surface, covers 1 % of this area

Sedwick and Moran Formations, undivided

Sand sheet deposits (Holocene) at surface, covers 0.9 % of this area

Sand sheet deposits

Ranger Limestone and Placid Creek Shale, undivided (Pennsylvanian; Missouri Series) at surface, covers 0.3 % of this area

Ranger Limestone and Placid Creek Shale, undivided

Dune sand sheet deposits (Holocene) at surface, covers 0.2 % of this area

Dune sand sheet deposits

Admiral and Coleman Junction Formations, undivided (Permian; Wolfcamp Series) at surface, covers 0.2 % of this area

Admiral and Coleman Junction Formations, undivided

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

High gravel deposits

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

Santa Anna Branch Shale