The Davis Mountains are an erosional remnant of a volcanic field that probably covered 5 to 10 times their present areal extent of approximately 2,000 square miles.

Geologic map that depicts the surface geology of Galveston and Chambers Counties and parts of Waller, Harris, Liberty, Jefferson, Orange, Brazoria, Matagorda, Wharton, and Fort Bend Counties.

Paleoenvironmental analysis of the alternating beds of the basal Cretaceous Glen Rose Formation in Central Texas indicates a cyclical alternation of subtidal through supratidal facies.

Geologic map that depicts the surface geology of Montgomery, San Jacinto, and Hardin Counties and parts of Madison, Trinity, Polk, Tyler, Jasper, Newton, Orange, Jefferson, Liberty, Harris, Waller, Grimes, Walker, and Robertson Counties.

Geologic map that depicts the surface geology of El Paso County and parts of Hudspeth. Jeff Davis, and Culberson Counties, Texas. The 12-page booklet indicates geologic formations, abbreviations, and ages. Published in honor of E.

Papers in this volume were presented at the Fourth Forum on Geology of Industrial Minerals sponsored by the Bureau of Economic Geology, The University of Texas at Austin, on March 14 and 15, 1968. The program and meetings were organized and directed by co-chairmen W. L. Fisher and P. U.

Tuff, tuffaceous sand and clay, bentonite, and sandstone containing abundant volcanic rock detritus are present in Gulf Coast Tertiary rocks ranging in age from Eocene to Pliocene.

Geologic map that depicts surface geology of Swisher, Briscoe, Hall, and Childress Counties and parts of Randall, Armstrong, Donley, Collingsworth, Hale, Floyd, Motley, and Cottle Counties.