This six-sheet set of oversize colorful geologic maps and cross sections presents new interpretations on the outcrop pattern and complex structure within the Upper Cretaceous Del Rio, Buda, Boquillas, Pen, Aguja, Javelina, and Cretaceous-Tertiary Black Peaks Formations of Big Bend National Park.

Although the mature, supergiant East Texas field on the west flank of the Sabine Uplift has been producing from the Upper Cretaceous (Cenomanian) siliciclastic Woodbine Group for more than 75 years, no modern comprehensive geologic study of it has been completed.

From 1952 to 1956, Pemex conducted a considerable amount of stratigraphic field work in the eastern Sierra Madre and in Laramide folds to the north across the Sabinas Basin.

Six interlocking regional stratigraphic cross sections of Lower Cretaceous strata (middle Albian-lower Cenomanian) of the Edwards and Stockton Plateaus of West Texas illustrate the vertical and lateral extent of lithostratigraphic units and distribution of facies and facies tracts.

Coalbed methane is playing an increasingly important role in meeting the energy needs of the United States. According to one estimate, this unconventional gas may supply 4-5% of the domestic natural gas in 1994.

Cretaceous rocks in the Southern High Plains, traditionally considered to be part of the High Plains aquifer and recharged by the overlying Ogallala aquifer, actually contain three aquifers with different recharge sources.

Sandstone in the Travis Peak (Hosston) Formation has been extensively modified by burial diagenesis. Permeability in much of the formation has been reduced to less than 0.1 md as a result of compaction, extensive precipitation of authigenic minerals, and minor pressure solution.

The Big Wells (San Miguel) reservoir in Dimmit and Zavala Counties, South Texas, produces from a broadly lenticular, wave-dominated deltaic sandstone encased in prodelta and shelf mudstones.

The Upper Cretaceous Olmos Formation in South Texas continues to be an active exploration target 60 years after oil was first discovered in this clastic assemblage. The shallow, oil-bearing formation was deposited on a broad, wave-influenced shelf. Sand accumulated in two depocenters.