The San Angelo Formation is a mid-Permian sandstone and mudstone sequence about 100 feet thick that crops out in North Texas and dips westward into the Midland Basin; it is composed of two superposed members: the basal Duncan Sandstone Member and the overlying Flowerpot Mudstone Member.

Geologic map that depicts the surface geology of Tom Green, Irion, and Reagan Counties and parts of Midland, Glasscock, Sterling, Coke, Runnels, Concho, Menard, Schleicher, Crockett, and Upton Counties, Texas.

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.

Geologic map that depicts the surface geology of Colorado, Lavaca, and Gonzales Counties, and parts of Hays, Caldwell, Bastrop, Fayette, Austin, Waller, Fort Bend, Wharton, Matagorda, Jackson, Victoria, De Witt, Karnes, Wilson, and Guadalupe Counties, Texas.

The Texas Coastal Zone is marked by diversity in geography, resources, climate, and industry.

The stratigraphic record yields evidence that each episode of clastic silicate deposition has been of limited duration and that each has been preceded and followed by a significant hiatus.

The Texas Coastal Zone is marked by diversity in geography, resources, climate, and industry.

This field guide is designed to provide an opportunity to observe a variety of facies that are the fundamental blocks with which principal depositional systems have been fabricated. Available data is provided and a genetic interpretation is proposed.

The Fredericksburg Group is one of three groups of rocks which comprise the outcropping Lower Cretaceous sediments in north central Texas. Four formations form this group; from the base upward these are the Paluxy, Walnut, Comanche Peak and Edwards (fig. 1).