EXTENT OF THE UNCONFORMITY. 69 



northern provinces in being of continental rather than marine character. 

 As the Carboniferous limestone occurs in the region to the northwest and 

 west, and also to the east between Kiu-kiang and Nan-king, Hu-nan 

 appears to represent a peninsula extending southwestward into the southern 

 sea. It is probable that the unconformity which defines the northern land 

 areas may have extended thus far south. 



The land area which is indicated by this marked unconformity was 

 probably a southeastern extension of the continental area which existed in 

 Mongolia and central Asia. We turn naturally to the observations of Loczy 

 in his journey from Si-an-fu to Lan-ch6u-fu, to ascertain the conditions at 

 the base of the Carboniferous in the province of Kan-su, but unfortunately his 

 route over the loess plateau avoided the exposures which are to be found only 

 in the deeper canyons, and he did not see the base of the Carboniferous. 

 The section of the Lo-pan-shan* is the only one which may have bearing 

 upon the unconformity in question. The exact locality is west of Pa-liang- 

 fu, near longitude 106, latitude 35 30'. He describes a limestone, which 

 he calls Kohlenkalk, but which may be upper Sinian, as being unconform- 

 ably overlain by bright-colored sandstones, marbles, and conglomerates, 

 which he assigns to the Ober-Karbon, i. e., Permian. If the underlying 

 limestone is indeed the Carboniferous, the base of that system is not seen. 

 If, on the other hand, it be the Sinian, the Carboniferous is wanting and is 

 here overlapped by the Permian. 



*Reise des Grafen Szchenyi, vol. i, p. 486. 



