The Woodbine Formation is composed largely of terrigenous sediment eroded from Paleozoic sedimentary and weakly metamorphosed sedimentary rocks of the Ouachita Mountains in southern Oklahoma and Arkansas and subsequently deposited in a complex of nearshore environments along the margins of the broadly subsiding Northeast Texas Basin. Three principal depositional systems are recognized in Woodbine rocks--a fluvial system, a high-destructive delta system, and a shelf-strandplain system.

A resource capability unit is an environmental entity--land, water, area of active process, or biota--defined in terms of the nature, degree of activity, or use it can sustain without losing an acceptable level of environmental quality. Units are established by recognizing elements of first-order environmental significance, whether dominantly physical, biologic, or chemical.

In recent years, exploration and mining of uranium have become a significant part of the Texas mineral scene, with Texas emerging as a leading uranium-producing state. At the end of 1970, Texas ranked third in reserves among the states, with ore reserves of 6.6 million tons. Continuation of the recent high level of exploration is shown by the 6.1 million feet of drilling in Texas during 1970, surpassed only by drilling activity in Wyoming.

The Quitman Mountains are part of a narrow mountain range that extends southeastward from near Sierra Blanca, Texas (85 miles southeast of El Paso, Texas), into northern Mexico. The range is typical of many desert mountains of the southwestern United States in that it projects abruptly above the breached bolsons that border it. Thus, the Quitman Mountains stand in stark contrast topographically and geologically to the Hueco Bolson on the west and the Red Light Bolson on the east.