Cretaceous sedimentary rocks and Tertiary intrusive, extrusive, and volcaniclastic rocks dominate the geology of the Hen Egg Mountain and Christmas Mountains quadrangles in the Big Bend region of Texas.

In the western Delaware Basin and southern Central Basin Platform of Trans-Pecos Texas, Upper Permian (Ochoan) evaporite strata host locally voluminous but notoriously unpredictable, sporadic deposits of biogenic native sulfur.

Successful development of low-permeability-sandstone gas reservoirs depends on an understandingof their natural fracture patterns and on predictions of the orientation of horizontal stresses.This report describes the preliminary results of fracture analysis of the Lower Cretaceous TravisPeak Form

This study is a product of ongoing Bureau of Economic Geology investigations, by means of geologic and petrophysical modeling, into the nature of reservoir compartmentalization or heterogeneity.

In 1983, the Bureau of Economic Geology published the Atlas of Major Texas Oil Reservoirs, a precedent-setting synthesis of key geological and engineering data on 450 major oil reservoirs grouped into 48 regional plays.