The High Plains region, the northern and western side of Texas from the Panhandle to the Pecos River, is physiographically a quadrangular, mesa-like area that rises perceptibly by sharp escarpments above the adjacent lowlands to the east and to the west. It is characterized by a constructional topography formed on thick deposits of wind-blown materials that blanket the region. The textures of these materials vary from east to west, the finest textures occurring in an eastward zone, the coarser or sandy textures in a westward zone, with a transitional zone in between. The natural vegetation of the High Plains region consists primarily of short grasses, the northern portion of the Texas High Plains being one of the most distinctive short grass regions of the United States. To the south is a considerable growth of mesquite shrubs. The deep sand strips, particularly at the southwest, are characterized by shinnery growth admixed with tall bunch grasses, yucca, and associated herbs. Most of the High Plains country lies in the black earth or Cheronzem soils zone-a belt of country extending from the lower Rio Grande and the southern portion of the Texas Gulf coast northward across the middle and northern Great Plains well into the plains of western Canada. The Texas portion of the black earth makes up most of the southern third of this soils zone as it occurs in the United States. Agriculturally, the middle sector of the black earth, which is also the middle sector of the Great Plains, is predominantly the hard winter wheat region of the United States. This region extends southward well into the High Plains, occupying most of the Texas Panhandle. South of the Plainview area, cotton and grain sorghums are the dominant crops.
Formerly the High Plains region was entirely a grazing country. The rainfall decreases toward the west and becomes more irregular in occurrence and distribution. As a consequence, the livestock range industry remains important throughout the western portions of the High Plains. The southern portion of the High Plains, particularly south of Lubbock, contains areas of somewhat broken topography; such lands are mostly devoted to grazing. The areas of deep sands including the shinneries of the southwestern portion of the High Plains are almost exclusively grazing lands. Although topographically the High Plains region is an upland, it overlies a great basin-the Permian basin-which is a part of the Great Plains geosyndine; the latter is a vast structural feature lying eastward of the Rocky Mountains. Although the surface of the High Plains consists of a veneer of deposits geologically recent, the region is underlain by a thick agglomeration of Permian deposits, below which are still older beds of the Early Paleozoic, which in turn rest on the pre-Cambrian basement.
In the Permian basin region occurs a complex of geologic features, the complicated character of which still poses unsolved problems even to the specialist in the geology of the area. In brief, however, the Permian basin consists of two sub-basins, the western Delaware basin and the eastern Midland basin, together with the West Texas, or Central Basin Platform in between. These sub-surface features are important for the oilfields of West Texas and southeastern New Mexico, which are aligned with reference to them. Great reserves make the High Plains one of the outstanding oil and gas regions of the state (see OIL AND GAS INDUSTRY). The area also possesses large deposits of minerals chemically precipitated, such as salt, potash, and gypsum, laid down in the different phases of the desiccating seas of Permian time. In the southern part of the High Plains, brines in shallow lakes and in shallow subsurface accumulations supply the raw materials for the production of salt cake.