ON VOLCANOES AND EARTHQUAKES. 353 



Those of America are among the most celebrated. 

 On the North-west coast, three were observed by 

 Captain Cook ; and others exist on various parts of 

 the coast between Alaska and California, in which 

 last district there are five. Along the Cordilleras of 

 Spanish America, they are found dispersed and inter- 

 mixed with extinct ones, from the Tropic of Cancer 

 to Terra del Fuego : and among the latter, Chimbo- 

 raco is noted for its great elevation. Here, they seem 

 to extend in rows nearly north and south ; but, in 

 Quito, they diverge from that line, being spread over 

 a space of seven hundred square leagues. The Cor- 

 dillera is also intersected in the latitude of 19 by an 

 east and west range of them, containing the recent 

 volcano of Jorullo. The chain of islands which ex- 

 tends from Alaska, contains seven in a state of ac- 

 tivity, and they are also found in the Gallipagos. In 

 the West India Islands, St. Christopher, St. Vincent, 

 Guadaloupe, and Nevis, are still active, and many 

 extinguished ones are also found. I have but just 

 noticed those found in the Pacific ocean, and may 

 refer to Arago for a more particular enumeration than 

 would be admissible here ; but the total number of 

 active ones known, amounts to nearly two hundred, 

 of which one half belong to the American continent. 



Of the general Characters and geological Connexions 

 of Volcanoes. 



The forms of volcanic mountains are peculiar. 

 They are generally lofty, and, when solitary, of a 

 conical form ; being also more or less truncated at 

 the summits. When active, or but recently ex- 

 tinguished, that truncation is accompanied by an 

 irregular cavity, which forms the crater. In Vesu- 

 vius, and in other Italian volcanoes, the crater is a 

 VOL. i. A A 



