The Canyon Group (Missourian Series) is a sequence of westward-dipping, genetically related carbonate and terrigenous clastic facies that crop out in a northeast-southwest belt across North-Central Texas.

Knowledge of the regional sand distribution and its relationship to formation temperature and pressure is a preliminary step in evaluating the geothermal resources of the Frio Formation.

Nitrogen isotope ratios of ammonium and nitrate ions from soil and water samples can be analyzed reproducibly with an experimental error of approximately +/-1 parts per thousand (ppt). Two isotopic ranges of soil nitrate are found in the soils of southern Runnels County, Texas.

The Lake Travis vicinity lies predominantly within a carbonate rock terrane and is the site of ongoing intensive residential development.

Change, both natural and man-induced, is a significant and defining element of the Coastal Zone. Man-induced change, by definition, can be controlled if desired.

The Houston-Galveston Area Council of Governments (HGAC) encompasses over 12,000 square miles of southeast Texas (fig. 1).

The stratigraphic record yields evidence that each episode of clastic silicate deposition has been of limited duration and that each has been preceded and followed by a significant hiatus.