Geologic sections showing the subsurface delineation of approximately 100 Stratigraphic units composing the Mesozoic and Cenozoic Eras illustrate the interrelation of these units across most of the Gulf Coastal Plain of Texas. The geologic names that constitute the nomenclature have been published, and the vast majority are approved for use by the U.S. Geological Survey. Four dip sections and four strike sections, extending from the land surface to a maximum of about 18,000 feet below sea level, provide continuity of correlation from the outcrop to the deep subsurface. Stratigraphic units containing water with less than 3,000 milligrams per liter concentration of dissolved solids are shown on the geologic sections and serve as an indicator of water quality in the Gulf Coastal Plain of Texas.