Incidence of bloating among approximately 600 clay samples from East Texas, ranging in age from Gulfian (Late Cretaceous) to Recent, correlates principally with clay mineralogy-and pH--together an indication of bulk composition--and to a lesser extent with texture, loss on ignition, and content o

Three closely spaced oblique-slip faults displace a Quaternary gravel and sand unit overlying Eocene Claiborne strata in the Trinity River Valley, Leon County.

Lignite development will place major demands on ground-water supplies.

Oakwood Salt Dome in Leon and Freestone Counties, East Texas, is under consideration as a nuclear waste repository.

Surficial geologic investigations at Palestine, Keechi, and Oakwood salt domes have provided information necessary for evaluating these domes as nuclear waste repositories. Diapir growth uplifted sediments to form domes and created complex radial faulting.

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.

Several microearthquake recording stations were operated as a network in the East Texas Basin beginning in June 1981. At least six certain and two probable earthquakes as well as hundreds of events of undetermined origin were recorded through August 1982.

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.

The Sabine Arch is a large (1 2,000 mi2 [31,000 km2]), low-amplitude anticline centered on the Texas-Louisiana border.