IO4 RESEARCH IN CHINA. 



The last statement runs contrary to the views of many geologists, and 

 particularly to the views of those who hold with the master, Suess, that the 

 present mountain ranges are a direct consequence of the compressing forces 

 that folded the strata within them. There are, indeed, two distinct points 

 of view, each of which is the outcome of observation in a region that by its 

 special character determines the inference. With a few exceptions, Euro- 

 pean geologists are dominated by the stupendous structures of the Alps, and 

 have neglected physiographic studies. American observers twenty years 

 ago discovered a new line of interpretation in physiography, and applying 

 it first to the Appalachians have since extended it to other ranges and con- 

 tinents. In the light of present knowledge it appears safe to generalize as 

 follows: Those mountain chains which exhibit folded stmctures of post-Eocene 

 development owe their elevation in part possibly to the original effects of that 

 compression, and in part to subsequent efforts of a force acting in the same 

 sense, but producing upwarps and downwarps that are independent of anti- 

 clines and synclines, yet related in general position and trend to the folded 

 chain as a whole. On the other hand, altitudes due to folded structures of the 

 Permo-Mesozoic or older epochs of diastrophism were long since planed away 

 by erosion, and though the structures may be involved in relatively modern 

 upwarps, they are not related to the existing elevation. This is true in 

 spite of the general fact, inherent in the broader continental and oceanic 

 features of the earth, that some zones of orogenic activity retain their 

 dynamic character from an early geologic date to the present, as witness 

 the Wu-t'ai-shan. 



There are thus two types. Of the former, characterized by post- 

 Eocene folding and later warping in the same sense, the Karpathians 

 are the best known example,* the structure and physiography of the Alps 

 being too obscure to serve as a type. The second, characterized by Permo- 

 Mesozoic folding, peneplanation, and relatively recent warping, is repre- 

 sented by the classic Appalachians. 



In a region where the relief is directly due to anticlinal elevations and 

 synclinal depressions the relation between the altitudes and the structures 

 must be such that the anticlinoria at least correspond to heights and the 

 synclinoria to lows. A case in point is that of the Lewis range in Montana, f 

 where the altitudes bear these relations. But these relations do not hold 

 for the mountains of Central China ; their heights and lows are related to 

 upwarps and downwarps, which are not coincident with the complex and 

 intruded structures of Permo-Mesozoic time, but are everywhere sculptured 



* European Studies, B. Willis, Carnegie Institution of Washington Year Book No. 4. Bau und Bild 

 der Karpaten, by V. Uhlig, in Bau und Bild Oesterreichs, Wien, 1903. 



t Stratigraphy and Structure of the Lewis and Livingston Ranges, B. Willis, Bull. G. S. A., vol. xni, 

 P- 346- 



