Geologic map that depicts the surface geology of Burleson, Lee, Washington, and Brazos Counties and parts of Burnet, Bell, Milam, Robertson, Madison, Grimes, Waller, Austin, Fayette, Bastrop, Caldwell, Hays, Travis, and Williamson Counties.

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 7-page booklet indicates geologic formations, abbreviations, and ages.

Lignite or low-rank coal is a major energy resource in Texas, providing energy since 1850. Prior to 1930, and the advent of abundant natural gas and oil, lignite was a major energy source.

Geothermal energy is rapidly becoming recognized, both in the United States and abroad, as a viable source of energy which can supplement fossil fuels for electric power generation.