Cores and supporting petrophysical data from 20 wells in McAllen Ranch field were analyzed. This Vicksburg field lies in northern Hidalgo County near the south end of the Texas Gulf Coastal Plain on the downthrown block of a major growth fault that merges with a glide plane dipping 5 degrees to the east beneath the field. The analyses provided a base for interpreting depositional environments.We grouped cored strata into four facies: (1) prodelta shales, (2) distal delta-front sandstones and shales, (3) proximal delta-front sandstones, and (4) distributary-channel sandstones.

Extensively cored cyclic evaporites of the San Andres Formation (Guadalupian) of the Palo Duro Basin, Texas Panhandle, provided fundamental information for interpreting evaporite depositional processes. These evaporites preserve exceptionally sensitive indicators of water-level fluctuation in their depositional environment: (1) sedimentary fabrics that formed during evaporite deposition; (2) sedimentary features, surfaces, and insoluble residues that formed during evaporite dissolution; and (3) diagenetic overprints that formed during evaporite brine evolution.