Geologic map that depicts the surface geology of Hardeman, Wilbarger, Wichita, Clay, Knox, Baylor, Archer, Haskell, Throckmorton, Young, and Foard Counties and part of Jack County, Texas. The 20-page booklet indicates geologic formations, abbreviations, and ages.

Lignite is a rediscovered energy in Texas because lignite-produced energy is 3 to 7 times cheaper than intrastate natural gas. Production has risen from 18,000 short tons in 1950 to 14 million tons in 1976 and will exceed 50 million tons by 1985.

Lignite occurs in three Eocene stratigraphic units--the Wilcox Group, Yegua Formation, and Jackson Group--and in three ancient depositional systems-fluvial, deltaic, and strandplain/lagoonal.

Lignite deeper than 200 ft (61 m) constitutes about 60 percent of the total lignite resources in Texas. Projections indicate that meeting future demand will require mining this deep-basin lignite.

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.