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 development will place major demands on ground-water supplies.

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.

Statistical analysis of chemical data on Texas Eocene coals revealed startigraphic and geographic trends in lignite quality. Chemical data on near-surface coals wre obtained from various private and public sources. Seams from deep-basin coals were compared.

Since 1979, the U.S. Geological Survey (USGS) has funded cooperative programs with coal-bearing states in an effort to provide current U.S. coal resource estimates that are calculated by uniform, computerized methods.

Coal is found in six areas in Texas, including the large North-Central Texas field, a distinctive cannel coalfield in Webb County, and Late Cretaceous-age coals near Eagle Pass.