Geologic map that depicts the surface geology of Carson, Gray, and Wheeler Counties and parts of Moore, Hutchinson, Roberts, Hemphill, Potter, Randall, Armstrong, Donley, and Collingsworth Counties.

Geologic map that depicts surface geology of Crosby, Dickens, and King Counties and parts of Hale, Floyd, Motley, Cottle, King, Lubbock, Lynn, Garza, Kent, and Stonewall Counties. The Lubbock Sheet honors the late Dr.

In the Great Plains the succession of gross ecological conditions through Neogene and Quaternary time may be interpreted from the stratigraphy, geomorphological history, buried soils, and fossil mollusks and plants.

The eastern margin of the High Plains in central western Texas affords particularly good opportunity for study of late Cenozoic geology.

The Ogallala formation extends from the north side of the Pecos Valley northward across western Texas, Oklahoma, Kansas, and Nebraska into southern South Dakota.

Studies of physiographic relations and of fossil molluscan faunas made in the Pecos River valley region (Val Verde County to the Texas�New Mexico border) reveal extensive, well-pedimented surfaces southwest of the river extending from the Davis Mountains to near the present channel.

The Red River rises in northeastern New Mexico and extends across northern Texas and east of the Panhandle serves as the northern border of that State. The late Cenozoic geology of the Red River basin has been studied intensively in northwestern Texas and in Louisiana.

Studies along the southern and southeastern borders of the High Plains have demonstrated the presence of outliers of fossiliferous Ogallala Formation in Borden and Scurry counties and have documented the occurrence of Pliocene deposition as far southeast as Sterling County.