Permian Choza Shale crops out in southeastern Coke County, Texas, and is overlain unconformably by 550 ft of coarse cross-bedded gray sandstone, chert conglomerate, and red beds, of which the lower 130 ft is San Angelo Formation and the upper 400 ft is San Andres Limestone. Evenly bedded fine-grained red sandstone and shale beds that are 675 ft thick and contain a 10-ft basal conglomerate lie on the San Andres and are divided in ascending order into the Grayburg, Queen, Seven Rivers, Yates, Tansill, Salado, Rustler, and Dewey Lake formations. These formations are separated in the subsurface by thin anhydrite beds that have been dissolved by ground water at their outcrop in central and western Coke County. Dewey Lake Sandstone in western Coke County is overlain unconformably by Cretaceous sandstone of the Paluxy Formation.

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