GEOLOGICAL RESEARCH IN EASTERN ASIA. 285 



The conclusion that mountains are recent growths — indeed, are in 

 some districts now actively growing — is far-reaching in effect on 

 theories of the earth's internal energy and its manifestations, 



Moimtaiyi Groivths of China. — The oldest topographic surface rec- 

 ognized in China was once in part a hilly region, in part a nearly 

 level peneplain, which stood but slightly above sea level during early 

 and perhaps middle Tertiary time. That surface has since been 

 warped. Where depressed it lies below sea level, buried under the 

 alluvial deposits of the Huang-ho and the Yangtse-kiang ; where ele- 

 vated it tops the summits of mountain masses, even the Wutai-shan, 

 at an elevation of 10,000 feet. Where the plain has been elevated, 

 valleys and canyons are sculptured in the subjacent rock masses, and 

 these, in their relative positions and in their forms, express the con- 

 ditions under which they have been modeled. These conditions have 

 varied from epoch to epoch, and the history of the changes is read in 

 the mountain forms. Through our observations in China we recog- 

 nize that the surface has been warped intermittently, episodes of rela- 

 tively active movement having alternated with those of comparative 

 quiescence. These variations distinguish stages of development 

 which are capable of arrangement in a general sequence parallel 

 with the history of mountains in North America. 



A discussion of the events of mountain growth is beyond the scope 

 of this preliminary report, but it is of interest to note that the great 

 ranges in eastern Asia, like those of western North America, are of 

 very recent development. Conspicuous among the mountains we 

 have seen are the Ho-shan of Shansi and the Hua-shan of Shensi. 

 They are ranges of great altitude, with bold, even fronts like the 

 Wasatch in Utah, and, like the Wasatch, they each define one 

 margin of a dislocation in the earth's superficial crust, along which 

 displacement has very recently occurred or is now going on. The 

 superb scenery of the great gorges of the Yangtse and of the mountain 

 region which extends north to the Huang-ho is a result of very recent 

 unwarping, in spite of which the larger streams have held their 

 courses, as the Columbia River has across the rising Cascade range. 



In addition to the interest which attaches to the history of moun- 

 tain growth in China for itself, and to the broad inferences which 

 may follow from a comparison with the mountains of North Amer- 

 ica, the study affords important criteria for the new science of physi- 

 ography, since the conditions in China have in some respects been 

 peculiar. Among the interesting problems upon which our physio- 

 graphic investigations throw light is that of the loess. 



