The State-owned submerged lands of Texas encompass nearly 6,000 square miles (15,540 km²) and extend from Mexico to Louisiana. The area includes the bays, estuaries, and lagoons, as well as the inner continental shelf 10.3 miles (16.6 km) seaward of the Gulf shoreline (fig. 1).

Precambrian sedimentary rocks and associated mafic and silicic igneous rocks in Central Texas underwent a single episode of regional metamorphism about 1,050 million years (m.y.) ago.

Geologic map that depicts surface geology of parts of Hudspeth, Culberson, Jeff Davis, and Presidio Counties, Texas. The 12-page explanatory booklet indicates geologic formations, abbreviations, and ages.

Potential geopressured geothermal reservoirs in the Vicksburg Formation are limited to Hidalgo County along the Lower Texas Gulf Coast.

Hot springs and wells in West Texas and adjacent Mexico are manifestations of active convective geothermal systems concentrated in a zone along the Rio Grande between the Quitman Mountains and Big Bend National Park.

The Upper Triassic Dockum Group of Texas and New Mexico is composed of 200 to 2,000 feet of complexly interrelated terrigenous clastic facies ranging from mudstone to conglomerate.

This report provides a data base for decisions about lignite mining and reclamation in the Wilcox Group of East Texas. Kaiser (1974, 1978) estimates that about 12.2 billion short tons of potentially strip-minable lignite resources occur in East and South Texas.