This cross section set traverses four Cenozoic depositional sub-provinces: the Rio Grande Embayment, San Marcos Arch, Houston Embayment, and Sabine Arch.

An active diapir forcefully intrudes its overburden, driven by diapir pressure that overcomes the resistance of the overburden strength. Possible causes of the driving pressure are differential loading of the source layer and a density contrast with the overburden.

Dipmeter analyses performed within McAllen Ranch field, Hidalgo County, South Texas, proved useful in finding reserves of natural gas. McAllen Ranch field produces from the Oligocene Vicksburg Formation on the downthrown, east block of a listric growth fault that merges with a flatlying glide plane beneath the field.

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.