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.

This guidebook is a reprinting of a field guide prepared by Shell Development Company as part of a three-day industrial short course for full-time college teachers in geology, conducted from March 30 to April 1, 1970, by Shell Development Company, Houston, Texas, in cooperation with AGI Council on Education in Geological Sciences. The guidebook includes excellent summaries and well-illustrated documentation of elastic depositional environments and related facies of the southeastern Texas Coast.

Tertiary rocks, including sandstone, conglomerate, shale, pyroclastics, tuff, and lava, are preserved in Big Bend National Park and in a much larger area to the west and northwest. Some of the rocks have distinctive characteristics that enable recognition by their lithology. Others are distinctly dissimilar, although they may have been deposited about the same time.

This report presents stratigraphic data and interpretations pertaining to the origin of a continental shelf-ocean basin sedimentary complex developed during Lower Cretaceous time in northern Coahuila, Mexico. This shelf was developed within a carbonate depositional regime and provides a specific descriptive example which should be useful in the development of a comprehensive process-response model of shelf origin.

The conservation movement has grown enormously in strength and breadth during the last decade as a result of widespread concern about natural resources and the quality of the environment. The Federal leadership broadened the definition of conservation to applied ecology and thereby put a meaning into the word that went far beyond its original sense. Conservation now includes all of the physical, social, and legal problems attendant on use of the land.