The Ellenburger Group (Lower Ordovician) of Texas is a laterally extensive peritidal carbonate shelf sequence. It forms a major deep oil reservoir, having estimated reserves of 1.15 billion barrels of oil, and it also contains an estimated 2.2 billion barrels of oil equivalent.

To recover gas remaining in solution, large volumes of brine must be produced from watered-out gas reservoirs in the Gulf Coast. Secondary gas recovery in a geopressured upper Frio (Oligocene) reservoir in Northeast Hitchcock and Alta Loma fields in Galveston County, Texas, requires the disposal of approximately 20,000 barrels of brine per day (bblld) into several disposal wells.

Remotely sensed features such as linear drainages, escarpments, ridges, and aligned playas have been identified on Landsat imagery (scale 1:250,000) of the Texas Panhandle and adjacent regions to allow comparison of these features with detailed regional and site-specific geologic data. Physiographic subdivisions of this area are the High Plains, Canadian Breaks, Rolling Plains, Pecos Valley, and Raton section.

This field guide summarizes recent interpretations of the upper Cenozoic stratigraphy of parts of the Southern High Plains and Rolling Plains in northwestern Texas and eastern New Mexico. Processes that formed lacustrine basins, which pond surface water on the High Plains that is recharged to the Ogallala aquifer. are also described. Field trip stops were selected to illustrate the depositional facies and paleosols of Cenozoic formations, Cenozoic local faunas, and lacustrine basins.