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

The publication comprises 24 structural dip cross sections, spaced 15 to 20 mi apart along the Texas coast, and 4 structural strike cross sections. Dip sections extend from near the Wilcox outcrop to the coastline.

The Smackover and lower part of the Buckner Formations (Oxfordian) comprise a thick regressive sedimentary sequence deposited on a Jurassic carbonate ramp. Four major depositional systems are recognized: (1) basinal, (2) low-energy open shelf, (3) high-energy shoal, and (4) sabkha.

The environmentally sensitive trace elements molybdenum, arsenic, and selenium are concentrated with uranium in ore deposits in South Texas. Cattle grazing in some pastures in mining areas have contracted molybdenosis, a cattle disease resulting from an imbalance of molybdenum and copper.

Upward-coarsening sandstone units of the Upper Cretaceous San Miguel Formation in South Texas were deposited in wave-dominated deltas during minor regressive phases, periodically interrupting a major marine transgression.

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.

Geologic map that depicts the surface geology of Comal, Bandera, Bexar, and Medina Counties and parts of Real, Kerr, Kendall, Hays, Guadalupe, Wilson, Atascosa, Frio, Zavala, and Uvalde Counties, Texas. The 9-page booklet indicates geologic formations, abbreviations, and ages.

In recent years, exploration and mining of uranium have become a significant part of the Texas mineral scene, with Texas emerging as a leading uranium-producing state. At the end of 1970, Texas ranked third in reserves among the states, with ore reserves of 6.6 million tons.