JEHOL UPLANDS

Wade-Giles romanization Ch'eng-te P'ing-yan, Pinyin Chengde Pingyuan, region of extremely complex and rugged topography in southwestern Liaoning province, northeastern Hopeh province, and southeastern Inner Mongolia Autonomous Region, China. The area is mostly composed of Precambrian granites, gneiss, and crystalline shales, with some later (Mesozoic) sedimentary rocks. Extensively folded along a northeast to southwest axis, the area is also extensively faulted along the same general structural lines, resulting in relatively recent outpourings of basalts and lavas, particularly in the upper part of the region. Generally, the upland descends in steplike formations from the high plateau area near Wei-ch'ang (Hopeh) and from the ranges forming the watershed of the interior drainage areas of Inner Mongolia (which reach elevations of some 5,9006,500 feet [1,8002,000 m]), down to the Chien-sheng and Nu-lu-erh-hu mountain ranges (about 3,950 feet in height), and finally to the Sung Range, running parallel to the coast of the Po Hai (Gulf of Chihli) at an average elevation of 1,6001,700 feet (488518 m). This general structure is complicated, especially in the southwest, by a number of minor ranges with a northwest to southeast orientation, and the whole area is deeply dissected by a complex river system. The topography is extremely rugged. Apart from the coastal region, the area falls into the drainage area of either the Luan River or the western tributaries (the Liao, Lao-ha, and Ta-ling rivers). Originally the areawhich is rather dry, especially in the northwesthad a cover of mixed deciduous and coniferous forest gradually merging into steppe (grassy plains) in the northwest. Most of the forest cover, however, was long ago destroyed, leaving a barren landscape of grassland and scrub.