Deep-water sandstones of the Oligocene-age Hackberry unit of the Frio Formation contain significant quantities of oil and gas and remain potentially one of the most productive exploration targets in southeast Texas.

Thirty-one low-permeability gas-bearing sandstones in 15 sedimentary basins were surveyed to delineate the major depositional systems and associated facies of each stratigraphic unit.

Post-Aptian strata (younger than 112 ma) in the East Texas Basin were strongly influenced by halokinesis and recorded the evolution associated sate structures.

The top of mushroom-shaped Oakwood salt dome is approximately 210 m (700 ft) beneath the boundary of Freestone and Leon Counties near the southwestern end of the East Texas Basin, The dome is surrounded by Jurassic, Cretaceous, and lower Tertiary marine and nonrnarine strata.

The State-owned submerged lands of Texas encompass almost 6,000 mi2 (15,540 km2). They lie below waters of the bay-estuary-lagoon system and the Gulf of Mexico and extend 10.3 mi (16.6 km) seaward from the Gulf shoreline (fig. 1).

Texas has long been a major oil province, accounting for nearly 40 percent of the historic production of crude oil in the United States. Texas now holds less than 30 percent of the Nation's proven reserves and less than 15 percent of its estimated as-yet-undiscovered oil.

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.

Since early 1977, the Bureau of Economic Geology has been evaluating several salt-bearing basins within the State of Texas as part of the national nuclear waste repository program, The Bureau, a research unit of The University of Texas at Austin, is conducting a long-term program to gather and in

Geologic characterization of evaporite deposits as potential host rocks for burial of radioactive waste must include hydrogeologic investigations at both local and regional scales.