The hydromechanical properties of the uppermost basement and of the basement–sediment interface influence multiple geologic processes of societal relevance, including the flow of groundwater; the accumulation of hydrocarbons, economic minerals, and geothermal resources; and the response of seismo

We studied the Hickory Sandstone Member of the Riley Formation, Central Texas, to assess the diagenetic history of a cratonic sandstone, which, in spite of its great age, remains porous and permeable where it has not been buried more than 1 km.

Geologic map that depicts the surface geology of Mason, Llano, and Gillespie Counties and parts of Menard, Kimble, San Saba, McCulloch, Edwards, Real, Kerr, Kendall, Blanco, Hays, Travis, Williamson, and Burnet Counties, Texas.

Middle and Upper Cambrian rocks and locally up to 90 feet of Lower Ordovician rocks in Central Texas, are here named the Moore Hollow Group.

Geologic map that depicts the surface geology of Mills County and parts of Runnels, Coleman, Brown, Comanche, Erath, Hamilton, Coryell, Lampasas, San Saba, McCulloch, Concho, and Menard Counties. The 21-page booklet indicates geologic formations, abbreviations, and ages.

Trilobites collected during the past 20 years from the Morgan Creek, Point Peak, and San Saba Members of the Wilberns Formation comprise 89 species assigned to 45 genera belonging to zones of the upper Franconian and Trempealeauan Stages of the Upper Cambrian Croixan Series.

The red upper unit of the Hickory Sandstone is a hematitic and goethitic sandstone containing a large reserve of potential low-grade iron ore.

Forty-three species belonging to 28 genera, 12 species of brachipods belonging to 8 genera, and 1 species of gastropods are described from the Morgan Creek, Point Peak, and San Saba Members of the Wilberns Formation in the Llano Uplift.