The High Plains Surface in Kansas

Abstract

The High Plains extend in a north-south belt for nearly a thousand miles (Fenneman, 1931, map) from south Texas to southern South Dakota and comprise the most extensive section of the Great Plains physiographic province. Western Kansas lies within the central High Plains (Fig. 1). This area, and the Llano Estacado of northwestern Texas and east-central New Mexico are probably most representative of the topography generally considered typical of this section (P1. I). In these areas the High Plains are actually a partly dissected high plateau, sloping generally toward the east and southeast, the region as a whole being characterized by broad reaches of flat, undissected and in many places undrained uplands between the valleys. The major valleys that cross this plateau are broad and have gentle side slopes that extend downward to relatively narrow flats. Minor valleys in many places are steep-sided narrow canyons. The Texas and New Mexico portion of the High Plains is terminated abruptly on the east and west by sharp escarpments capped by the Ogallala formation (Pls. 2B and 3B). In southern Kansas, Fenneman's (1931) eastern boundary of the High Plains is drawn at a minor topographic break located some 20 to 25 miles west of a prominent dissected escarpment in his Plains Border section. Northward, along the Arkansas Valley no perceptible topographic feature is found to mark the eastern limit of Fenneman's High Plains. Still farther north, in central and northern Kansas as far as the Nebraska line, the eastern margin is gradational across the belt of country called by Fenneman the Plains Border section (P1. 2C). This section contains two irregular east-facing escarpments produced by the eastern outcrop of the Fort Hays limestone (P1. 3A) and the Greenhorn limestone, but the eastern limit of the Ogallala formation produces an escarpment at only a few places. EARLY CONCEPTS OF HIGH PLAINS SURFACE