USGS Home
Contact USGS
Search USGS

Mineral Resources > Online Spatial Data > Geology > by state > Texas Geology

Geologic units in Rockwall county, Texas

Ozan Formation (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]) at surface, covers < 0.1 % of this area

Ozan Formation

Lithology: clay or mud

Neylandville and Marlbrook Marls, undivided (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]) at surface, covers 11 % of this area

Neylandville and Marlbrook Marls, undivided

Lithology: clay or mud

Wolfe City Formation (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]) at surface, covers 5 % of this area

Wolfe City Formation

Lithology: sand; silt; mudstone

Pecan Gap Chalk (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]) at surface, covers 0.1 % of this area

Pecan Gap Chalk

Lithology: limestone; sand; clay or mud; limestone

Terrace deposits (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 3 % of this area

Terrace deposits

Lithology: terrace; sand; gravel; silt; clay or mud

Neylandville Marl (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]) at surface, covers 9 % of this area

Neylandville Marl

Lithology: clay or mud

Marlbrook Marl (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]) at surface, covers 56 % of this area

Marlbrook Marl

Lithology: clay or mud; limestone

alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 4 % of this area

alluvium

Lithology: sand; silt; clay or mud; gravel

Nacatoch Sand (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]) at surface, covers 0.5 % of this area

Nacatoch Sand

Lithology: clay or mud; sand; sandstone