Study of Permian, Cretaceous, and Cenozoic rocks in the 30 Kent quad- rangle is important to an understanding of the geology of Trans-Pecos Texas. Most of the Cretaceoua rock units of central Texas lose their lithostratigraphic identity when traced into west Texas.

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 Information from published and unpublished sources was checked and supplemented by field investigations.

The departure point of the Villa Capri Motor Hotel may be gone, but the geologic information within Guidebook Number 3 remains relevant to this day:  "The four stops of this field trip are in the Upper Eocene (Jackson) and Oligocene volcanic ash and bentonite beds, which crop out about

Stones and minerals that are sufficiently beautiful, durable, and rare are known as gemstones. A gemstone with only one of these qualities is less desirable than one with all three.

In the past 100 years, more than 100 names have been used to designate parts or all of the outcropping Midway and Wilcox rocks in the Gulf Coastal Plain; less than half of these names are used currently by Coastal Plain geologists, and the validity of some of the remaining named rock units has be

Almost everyone has seen the fossilized remains of prehistoric plants or animals. These might have been the skeleton of a gigantic dinosaur, the petrified trunk of an ancient tree, or the shells of snails or oysters that lived in the great seas that covered Texas millions of years ago.

Three mappable members in the upper part of the Thrifty formation (Blach Ranch limestone, unnamed shale, and Breckenridge limestone), two in the lower part of the overlying Harpersville formation (Quinn clay and Crystal Falls limestone), and six minor lentils, all in the outcropping Cisco group,