single great uplift, with more or less buckling of the crust into long swells. The minor, albeit to the traveler the most impressive features, such as valley, ridge, and peak, appear to be wholly the product of aqueous, supplemented by glacial erosion. On every side of Chinese Turkestan, as appears from my own observations and those of others, the so-called mountains are in reality plateaus of comparatively slight relief except on the edges. Potentially, to be sure, they are mountainous, for they have the necessary elevation, and the typical contorted rock structure. In time they must be cut to pieces by rain and rivers, and must assume forms like those of the Alps, where few or no traces of a plateau can be detected. On the whole, the Karakorum plateau and the other plateaus of Central Asia strongly support the new geological view that the great mountain systems of the world originate as plateaus, that is, as uplifted blocks or arches of the earth's crust, which are raised up not as individual ranges, but as broad regions, to be carved later into the form to which we usually apply the name of mountains.
The descent from my mountain and the little bird was easy, as I slid on the snow for nearly two thousand five hundred feet. The bird was probably a migrant on the way to Turkestan. Henderson, the only ornithologist who has ever worked in the country, says that some of the most delicate of the birds of India, little warblers with the most wavering, uncertain flight, cross the cold plateau of Karakorum to spend the summer in Chinese Turkestan. It is marvelous that such seemingly impotent creatures should be able to cross two hundred miles of bleak desert amid
IIIFカラー高解像度
