Abstract The Southern Great Plains physiographic sub-province lies south of the Cimarron River, which crosses the plains at ~37° N latitude (Fig. 1). The sub-province is bounded on the west by the Southern Rocky Mountains Province and Sacramento section of the Basin and Range Province. On the east the Great Plains are bounded by the Caprock Escarpment and are separated from the Gulf Coastal Plain by the Balcones Escarpment. The southern Great Plains physiographic sub-province is divided into the Pecos Valley and Raton sections on the west, the High Plains section on the east, and the Edwards Plateau on the south. “In the public mind the Great Plains are thought of as a vast monotonous plain that lacks scenic interest, but has to be crossed to reach the scenic Rocky Mountains to the west“ (Thornbury, 1965, p. 287). Whereas this region clearly lacks areas of high relief and thus scenic wonders, it does contain some of the most extensive deposits of Tertiary and Quaternary sedimentary and volcanic rocks that have been recognized in North America. These units are commonly well exposed along the banks of stream systems being incised into the Great Plains and in the high scarps that bound the High Plains. Numerous descriptions of the Quaternary geology and geomorphology of the Southern Great Plains have been published since the first reports became available late in the 19th and early 20th centuries (Johnson, 1901; Baker, 1915). Of these, useful reviews or

Abstract Lingos strata (Figs. 1, 2) are well exposed at localities in Hall, Briscoe, and Floyd counties, Texas. Except where the formation is dissected or where remnants of bedrock project through it, the Lingos terrane is a smooth continuous geomorphic surface sloping southeastward approximately 80 ft/mi (15 m/km) near the escarpment and 40 ft/mi (7.5 m/km) farther east. The route between the Field Guide localities described here crosses this geomorphic surface, within the area covered by the Plainview sheet of the Geologic Atlas of Texas (Barnes, 1968). However, none of the deposits now recognized as the Lingos formation are shown on the atlas or other maps published before 1984. Topographic maps (7½-minute) covering the localities in this Field Guide are: Turkey, Folley, Quitaque and Lake Theo.