REPORT OF THE SECRETARY. 37 



winter and following spring from Peking through the mountains of 

 western Chihli,and again from Peking, beyond the great wall of China, 

 and westward on the plateaus along its southern edge to its 112th me- 

 ridian, returning by a route south of the great wall. In the winter 

 of 1864-'65 he went from Peking across the plateau of Central Asia- 

 to Siberia. 



The almost total absence of observations of a geological character 

 throughout this wide field, renders any information in regard to it of 

 considerable interest. The facts stated are principally derived from 

 the personal observations of the explorer, together with such inform- 

 ation as could be obtained from Chinese works which treat of the 

 geography of the empire, or bear upon its mineral productions. The 

 principal results arrived at are as follows: 



There is reason to believe that there exists throughout China an 

 immense development of Devonian limestone, which rises to the sur- 

 face in all the larger ridges, and attains in some places a thickness of 

 over 10,000 feet. The formations beneath this limestone, as 'far as 

 they were seen, are either granitic rock or metamorphic schist un- 

 conformably stratified as regards the limestone. Overlying the lime- 

 stone there exists in almost every part of the country a great coal- 

 bearing formation of sandstones, shales, conglomerates, <fcc, in 

 nearly, if not quite, conformable stratification as regards the floor on 

 which they rest. The fossil plants obtained from this formation are 

 considered supra-carboniferous, and it is supposed that the coal 

 fields of China, which vie with our own in extent, are referable to 

 the Triassic period. Although from the limited range of actual ob- 

 servation it would be too much to assert that there is a total absence 

 of any later formation than these coal measures, still the author failed 

 to observe any traces of them. 



Only two systems of elevations occur in China of sufficient import- 

 ance to have left a marked impress on the surface. These are the 

 northeast-southwest and east-west. 



The northeast system determines the outline of Asia east of the 

 110th meridian, and coincides with the middle course of the Yangtse 

 Kiang and the lower course of the Amur. 



The east-west system exists in western China in the Min mountains 

 and in the Nanling range, and determines the general course from 

 west to east of the'three principal rivers of the south of China. 



The upheaval of the northeast system began after the deposition 

 of the great Devonian limestone formation, and appears to have risen 

 slightly during the formation of the coal measures, but its greatest 

 elevation was after the latter had been deposited. 



