a7id their Connexion with Volcanos. 73 



is situated to the south of the same chain, is encompassed by 

 shallow pools of water. 



Thus it appears, that even if we admit the information given 

 with respect to places, of which no European has yet published 

 a report from personal inspection, there is nothing irreconcile- 

 able with the general law, which seems to prevail in other parts 

 of the globe, with regard to the vicinity of large masses of water 

 being most favourable to the development of volcanic energy. 



It may be true, as Humboldt has observed, that this relation 

 depends in part upon the configuration of the earth's surface in 

 the neighbourhood of the sea, and the inferior resistance opposed 

 in such situations to the escape of the melted matter. 



It may also be true, that where ancient revolutions have pro- 

 duced fissures in the crust of the earth at a distance from the 

 sea, phenomena of a genuine volcanic character may occasionally 

 manifest themselves, and hence, as we so frequently observe hot 

 and carbonated springs near extensive faults or other disloca- 

 tions of the strata, so in countries much subject to volcanic ope- 

 rations, we may sometimes meet with burning mountains at a 

 distance from the sea, as we find to be the case at Jorullo in 

 Mexico, and at Tolima in the central Andes. 



I can also readily understand the occurrence of volcanos in 

 the depressed portions of Central Asia contiguous to large and 

 numerous lakes ; nor is it material, whether these lakes shall 

 turn out to be salt, like the Caspian Sea or the Lake of Aral, 

 or to contain only fresh water. 



It is quite a misconception to suppose, as the writer of an 

 article on Ly ell's Geology in the Quarterly Review appears to 

 do, that the advocates of the chemical theory of volcanos ever 

 regarded sea-water as the necessary cause of subterranean move- 

 ments. It is the depth, and not the peculiar constitution of the 

 ocean, which supplies us with a reason of the greater frequency of 

 volcanic phenomena in its immediate neighbourhood, since this 

 depth will cause it to exert a pressure sufficient to inject a por- 

 tion of its contents through the fissures of the subjacent rock, 

 and thus to maintain a more ready communication with the 

 combustible materials existing in the interior of the globe, than 

 elsewhere prevails. When in this manner it becomes the agent 



