ON ITS EXTERIOR. VOLCANOES. 417 



remarkable geological phenomenon, for it indicates a 

 former water-communication of very extensive character. 

 May we suppose that the many and various subsidences, 

 to which this central part of Asia has been exposed 

 over a wide extent, may have exceptionally given occa- 

 sion, on the convexity of the continental swelling, to 

 circumstances and relations similar to those at the 

 borders of elevation-fissures on coasts ? 



Well-assured reports made to the Emperor Kanghi 

 have made known the existence of a now extinct volcano 

 far to the east, in the north-west part of Mantchou 

 Tartary, in the district about Mergen, which is probably 

 in 48J N. lat. and 122 E. long, from Greenwich. The 

 eruption of scoriae and lava from this Mount Bo-schan, 

 or Ujun-Holdongi (the Nine Hills), about fourteen miles 

 south-west of Mergen, took place in January 1721. 

 The hills of scoriae which were thrown up are said, by 

 the persons whom the Emperor Kanghi sent to examine 

 the effects, to have occupied a space of twenty-four 

 miles in circumference, and the same authorities stated 

 that a current of lava, by damming up the river Udelin, 

 occasioned the formation of a lake. From less circum- 

 stantial Chinese accounts, it would appear that Bo-schan 

 had had an earlier igneous eruption in the seventh 

 century. The distance from the sea is about 420 geo- 

 graphical miles ; more than three times the distance of 

 the volcano of Jorullo from the sea, and similar to that 

 of the Himalaya, ( 572 ) We owe these interesting notices 

 to W. P. Wassiljew (G-eograpK Bote, 1855, Heft 5, S. 

 31); and to a paper by Semonow (the learned translator 

 of Carl Eitter's Erdkunde), in the 17th volume of the 

 Memoirs of the Kussian Imperial G-eographical Society. 



TOL. IV. E E 



