Geologic units in Hardeman county, Texas

Blaine Formation (Permian; Guadalupe Series) at surface, covers 52 % of this area

Blaine Formation

Sand sheet deposits (Holocene) at surface, covers 21 % of this area

Sand sheet deposits

Dune sand sheet deposits (Holocene) at surface, covers 12 % of this area

Dune sand sheet deposits

Clear Fork Group (Permian; Leonard Series) at surface, covers 6 % of this area

Clear Fork Group

San Angelo Formation (Permian; Guadalupe Series) at surface, covers 6 % of this area

San Angelo Formation

Alluvium (Holocene) at surface, covers 3 % of this area

Alluvium

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

Quaternary deposit, undivided

Terrace deposits (Pleistocene and Holocene) at surface, covers 0.5 % of this area

Terrace deposits

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

WOODWARD- Lenticular and interfingering deposits of gravel, sand, silt, and clay. Generally light-tan to gray. Thickness along major streams ranges up to 100 feet and probably averages 40 feet; along minor streams the thickness ranges up to 45 feet and probably averages 20 feet. ENID- Sand, silt, clay, and locally gravel. Maximum thickness ranges from 30 to 80 feet (9 to 24 m) along major streams and from 0 to 60 feet (0 to 18 m) along minor streams. TULSA- Gravel, sand, silt, and clay. TULSA- Gravel, sand, silt, and clay. OKLAHOMA CITY- Sand, silt, clay, and lenticular beds of gravel. Thickness ranges from about 30 to 100 feet and probably averages about 50 feet along major streams. Along minor streams, thickness ranges from a few feet to about 50 feet and probably averages about 25 feet. LAWTON- Sand, clay, and gravel as much as 50 feet (15 m) thick; Shown only along major streams and tributaries. ARDMORE-SHERMAN- Gravel, sand, silt, and clay, including low terraces; thickness, about 25 to 100 feet. McALESTER TEXARKANA- Gravel, sand, silt, and clay, including low terraces about 30 feet above channels; thickness, about 50 feet along Little River and 110 feet along Red River.