The Upper Cretaceous Olmos Formation in South Texas continues to be an active exploration target 60 years after oil was first discovered in this clastic assemblage. The shallow, oil-bearing formation was deposited on a broad, wave-influenced shelf. Sand accumulated in two depocenters.

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

In order to better understand the control exerted by fractures on the recharge and production zones of limestone aquifers, the authors delineated surficial fracture zones in the southern Edwards Plateau, Texas. Lineations were marked on nearly 200 mosaics scale of 1:24,000.

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.

The stratigraphic record of the Lower Cretaceous Trinity Division in Central Texas, as revealed by extensive outcrop investigation, is that of a shallow sea transgressing the southern flank of the ancient Llano Uplift.