USGS Home
Contact USGS
Search USGS

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

Geologic units in Webb county, Texas

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

Terrace deposits

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

Yegua Formation (Phanerozoic | Cenozoic | Tertiary | Eocene-Middle) at surface, covers 17 % of this area

Yegua Formation

Lithology: clay or mud; sandstone; limestone; coal

Laredo Formation (Phanerozoic | Cenozoic | Tertiary | Eocene-Middle) at surface, covers 17 % of this area

Laredo Formation

Lithology: sandstone; clay or mud

Frio Clay (Phanerozoic | Cenozoic | Tertiary | Oligocene) at surface, covers 1 % of this area

Frio Clay

Lithology: clay or mud

Jackson Group, undivided (Phanerozoic | Cenozoic | Tertiary | Eocene Oligocene) at surface, covers 22 % of this area

Jackson Group, undivided

Lithology: clay or mud; sandstone; siltstone

sand sheet deposits (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 2 % of this area

sand sheet deposits

Lithology: sand; silt

Bigford Formation (Phanerozoic | Cenozoic | Tertiary | Eocene) at surface, covers 3 % of this area

Bigford Formation

Lithology: siltstone; sandstone; clay or mud

Quaternary deposit, undivided (Phanerozoic | Cenozoic | Quaternary) at surface, covers 3 % of this area

sand, silt, clay, and gravel. locally indurated with calcium carbonate (caliche); includes point bar, natural levee, stream channel, sand dune, terrace, alluvial fan, landslide bolson and playa deposits

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

alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 5 % of this area

alluvium

Lithology: sand; silt; clay or mud; gravel

Indio Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene) at surface, covers 0.3 % of this area

Indio Formation

Lithology: fine-grained mixed clastic; coal

Catahoula Formation (Phanerozoic | Cenozoic | Tertiary | Oligocene) at surface, covers 0.7 % of this area

Catahoula Formation

Lithology: mudstone; sand; tuff; sandstone; conglomerate

El Pico Clay (Phanerozoic | Cenozoic | Tertiary | Eocene) at surface, covers 16 % of this area

El Pico Clay

Lithology: clay or mud; sandstone; coal

Goliad Formation (Phanerozoic | Cenozoic | Tertiary | Miocene) at surface, covers 6 % of this area

Goliad Formation

Lithology: clay or mud; sandstone; mudstone; carbonate; limestone; conglomerate

Carizzo Sand (Phanerozoic | Cenozoic | Tertiary | Eocene) at surface, covers 0.4 % of this area

Carizzo Sand

Lithology: sandstone

Catahoula Formation and Frio Clay, undivided (Phanerozoic | Cenozoic | Tertiary | Oligocene) at surface, covers < 0.1 % of this area

Catahoula Formation and Frio Clay, undivided

Lithology: clay or mud; mudstone; tuff; sandstone; sand; conglomerate

Uvalde Gravel (Phanerozoic | Cenozoic | Tertiary Quaternary | Pliocene Pleistocene) at surface, covers 3 % of this area

Uvalde Gravel

Lithology: gravel; chert