xxviii Physical and Geognostic 8ii(jge8tions, 



does not, as yet, comprise the scientific results of that 

 expedition. 



Proceeding- northwards, the volcanoes are more densely 

 crowded, and are found arranged in series. Of the fifty- 

 four which I enumerated as still in activity among the islands 

 of Eastern Asia, there are thirty-four on the Aleutian, 

 and ten on the Kurile Islands. The Peninsula of Kamts- 

 chatka contains nine volcanoes, which have been in activity 

 within the historic period. Lying under the 54th and 60th 

 degrees of northern latitude, we see a long strip of sea- 

 bottom between two continents undergoing a perpetual pro- 

 cess of destruction and re-arrangement. 



The South Sea, the superficial extent of which is one- 

 sixth greater than that of the entire solid crust of our , 

 planet, actually presents a smaller number of active vol- 

 canoes, less vents for communication between the centre 

 of the earth and its atmospheric envelope, than the single 

 Island of Java! Out of 40 volcanic cones, including- 

 those which are extinct, only 26 have been seen in eruption 

 during the historic period. They are not scattered at 

 random, but, on the contrary, as was pointed out by Mr. 

 James Dana, the ingenious geologist of the great United 

 States Exploring Expedition, imder the command of Capt. 

 Wilkes (1838-42), they have been thrown up, at widely 

 extending clefts, communicating by submarine mountain 

 systems. They are arranged in groups and distinct regions, 

 analagous to the mountain chains of Central Asia and 



