This folded transparent map is at the same scale as its corresponding Geologic Atlas of Texas (GAT) sheet and can be superimposed on it to compare gravity information with surface geology.

Geologic map that depicts the surface geology of Gaines and Andrews Counties and parts of Yoakum, Terry, Dawson, Martin, Winkler, Ector, and Midland Counties, Texas. The 5-page booklet indicates geologic formations, abbreviations, and ages.

Electrical images in boreholes are becoming increasingly important in interpreting the rock record.

The Leonardian Spraberry Formation is a major oil-producing formation of the Permian Basin, accounting for more than 700 million barrels of oil produced from heterogeneous submarine-fan reservoirs.

The geographic distribution, lithology, thickness, and paleontology of the subsurface Woodford in the Permian basin are described and illustrated.

The Upper Triassic Dockum Group of Texas and New Mexico is composed of 200 to 2,000 feet of complexly interrelated terrigenous clastic facies ranging from mudstone to conglomerate.

San Andres oil constitutes more than 80 percent of the total production from the Northern Shelf of the Midland Basin, Texas.

The San Andres Formation on the Northern and Northwestern Shelves of the Midland Basin is a progradational stratigraphic unit consisting predominantly of carbonate facies. Lithofacies include dolomite, laminated anhydrite and dolomite, massive bedded anhydrite, limestone, salt, and red beds.

The Ogallala aquifer, which underlies the Southern High Plains, consists of the saturated sediments of the Neogene Ogallala Formation. The aquifer is the main source of water for the High Plains of Texas and New Mexico and is being severely depleted by extensive pumpage for irrigation.

Pervasively dolomitized, anhydritic carbonates of the upper San Andres Formation in the Emma field of West Texas constitute an upward-shallowing sequence of lithofacies representing four major depositional environments.