MORPHOLOGY OF THE CHANG-TANG. 67
slightly undulating line which only at two or three points is interrupted by dark mountains. High ranges or snow are not in sight. No lakes are visible, only a few white patches which need not be salt. Some slopes are yellow as if covered with grass. The distance is, however, too great for allowing us to characterize the country. So much is clear: it is an enormous plateau-land so far as the eye sees, resembling the open ocean with flat rollers. Here, as well as elsewhere, one also gets the impression that the ranges nearly always are stretching east and west, and that they very seldom are continuous for any considerable length. It seems easy to pass to the S. E. without crossing any high passes. In the course of a month's journey we have also obtained a very graphic idea of the general morphological laws prevailing over Tibet as a whole. In the west, crossing the Chang-lung yogma, we left behind us the wild accentuated peripheric country with its deep-cut valleys and its vertical lines in the landscape, and entered the flat open plateau-land with extremely flat valleys and prevailing horizontal lines. To the north we only saw in the distance the mighty continuous mountain ranges which belong to the Kwen-lun System and constitute the northern marginal ranges of the high flat plateau-land of Tibet. The latter, with its insignificant relative altitudes and its enormous absolute heights, we have to cross diagonally to the S. E. until we again reach the continental water-parting and the southern marginal ranges, all of them belonging to the Transhimalayan mountain system. The most graphic impressions of the mountain country as a whole, one always gets from the passes. From them one dominates enormous areas of country without being preoccupied by too much details. It is the great characteristic features one sees from them. From this point of view as well, the panoramas are a very great help to the maps and to the description given in the text.
We leave the valley which goes down from the pass to our left, and cross the slopes to the S. E. The view to the south which was hidden from the pass, now by and by becomes visible. To the S. E. is a black range of moderate height stretching east and west. The peaks of its eastern half are pyramidal, those of the western rounded. There seem to be some easy passes over the range, though in this respect it is easy to make mistakes. Between us and the range there is an open latitudinal valley. The country is extremely desolate and there is no sign of animal life, no tracks, not even dung, and water is nowhere to be seen. The ground is red, yellow and white. Only yapkak is growing here. Between low, flat hills we follow a shallow valley without gravel, which finally emerges into the latitudinal valley, the chief erosion bed of which is directed to the N. 65° E., though the fall of the valley, as usual, is difficult to determine. It is situated between low hills of the finest red, green or yellow dust. Even in its bed there is no gravel. Only occasionally there is a narrow belt of fine gravel on the slopes. At the lee side or east of every
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