Benthic samples were collected on a 1-mi grid from Copano Bay, Texas, in March and April, 1976. Seventy-four molluscan species, including 33 pelecypods, 40 gastropods, and 1 scaphopod were taken from 93 stations in Copano Bay. Molluscan distribution was correlated with gross sediment, salinity, feeding type, and total organic carbon content.

Lower Permian (Wolfcampian) strata of the Palo Duro Basin consist of thick, terrigenous clastic and carbonate facies that were deposited in (1) fan-delta, (2) high-constructive delta, (3) carbonate shelf and shelf-margin, and (4) slope and basinal systems.

The environmentally sensitive trace elements molybdenum, arsenic, and selenium are concentrated with uranium in ore deposits in South Texas. Cattle grazing in some pastures in mining areas have contracted molybdenosis, a cattle disease resulting from an imbalance of molybdenum and copper.

The Catahoula Formation is composed of ancient fluvial sediments that controlled a wide range of water/sediment interactions responsible for uranium mobilization, transportation, and concentration.