ON VOLCANOES AND EARTHQUAKES. 369 



other sources could such masses of matter he elevated 

 from the hottom of a deep sea. 



The same depth is proved by the obvious con- 

 nexion which subsists among the Italian volcanoes ; 

 and if, as formerly suggested, a large portion of that 

 country has been raised from the bottom of the ocean, 

 the source of expansion must lie very deep in the 

 earth. The phenomena of earthquakes, the effects 

 of which are often propagated to such enormous dis- 

 tances from their immediate seat, prove the same 

 theory ; as it will immediately be shown that they 

 arise from volcanic actions. 



It might be inferred from the antient volcanoes of 

 Auvergne, that the place of the heat was one pro- 

 longed chasm, the fires of which, issuing from a 

 great depth, have found a vent in different places; and 

 this opinion is strongly confirmed by the American 

 volcanoes, particularly by the circumstances with 

 which the eruption of Jorullo was attended. There is a 

 narrow belt, lying between the parallels of eighteen 

 and twenty-two degrees, in New Spain,in which many 

 burning and extinct volcanoes are situated. That a con- 

 tinued fire exists here, is proved by the presence of 

 boiling springs, by the occasional eruption of smoke, 

 by frequent noises or explosions, and by earthquakes. 

 In this line are the volcanoes of the Pic d'Orizaba, 

 la Puebla, Nevado de Toluca, and Colima ; that of 

 Jorullo lying in the same parallel, and nearly at right 

 angles to the Cordillera of Anahuac. This line, ex- 

 tending for one hundred and thirty leagues and up- 

 wards, seems to indicate the existence of a volcanic 

 chasm, which may probably extend even to the Ar- 

 chipelago of Revellegedo, and. may also be the com- 

 mon deep seat of the whole. Hence the great depth 

 of the volcanic regions is here indicated by a species 



VOL. j. j* B 



