Upper Miocene, Pliocene, and Pleistocene deposits in the subsurface of the central Coastal Plain of Texas were subdivided into six operational units comprising the surface-defined Fleming, Goliad, Willis, Lissie, and Beaumont Formations.

The Sligo and Hosston Formations of Aptian age occur over thousands of square miles in the subsurface of South Texas.

Oversize color geologic map that depicts surface geology of Dimmit, LaSalle, and McMullen Counties and parts of Maverick, Zavala, Frio, Atascosa, Karnes, Wilson, Live Oak, Jim Wells, Duval, and Webb Counties, Texas. The 6-page booklet indicates geologic formations, abbreviations, and ages.

The increasing demand for uranium combined with the improving economics of uranium production have resulted in a significant upsurge in exploration and mining efforts in the South Texas Coastal Plain uranium province. Texas ranks third in U.S. uranium production.

Geologic map that depicts the surface geology of parts of Webb, Duval, Jim Wells, Kleberg, Brooks, Jim Hogg, and Zapata Counties

A preliminary study of the Frio sand distribution and formation temperatures and pressures was undertaken in order to define prospective areas in which a more detailed reservoir analysis is necessary prior to the selection of a site for a geothermal well.

Tuff, tuffaceous sand and clay, bentonite, and sandstone containing abundant volcanic rock detritus are present in Gulf Coast Tertiary rocks ranging in age from Eocene to Pliocene.

This report is a compilation of all available data on mineral resources (exclusive of oil and gas) in 39 south Texas counties. Information from published and unpublished sources was checked and supplemented by field investigations.