CONCHO LOGY. 



shells themselves had evidently been in a heated state from 

 some subterraneous cause, previous to their being deposited 

 by the great diluvial commotion which removed them from 

 their original habitation. The inner substance of the shells 

 seemed evidently to consist of an animal substance, incine- 

 rated and carbonized ; and in some of the Tel Unas the surface 

 was full of cracl.s, and discoloured in such a manner as 

 could only happen from a sudden and violent degree of 

 heat. These are to be considered as evident traces, in this 

 instance, of some volcanic cause having existed at a distant 

 period of time; and modern discoveries have confirmed 

 the idea of volcanos being found in almost every country 

 known at present: such is the hill of Cloud Thorpe, in 

 Derbyshire, and of Cadcr Idris, in North Wales. But it is 

 plain that volcanos are not peculiar to mountaineous countries, 

 although any mountain that is very high and conical may 

 be suspected to be volcanic, witness Teneriffe, the Andes 

 and Cordilleras in Peru, with many others. In Italy, which 

 with the surrounding islands and coasts, may be called the 

 modern Laboratory of Volcanos; it is frequently observed 

 even by the evidence of the present century, that many 

 small islands and even continents, become formed from the 

 very sea itself by the upheaving of subterraneous volcanos, 

 causing at the same time a subsidence in some regions from 

 the falling in of strata, and in others the accretion of moun* 

 tains and hills by the gradual deposition of their mineral 

 products. Some great external revolution of the waters 

 must however be supposed once to have existed, to account 

 for the phenomena of vegetable and animal remains found 

 in continents now so far distant from the Sea. Perhaps the 

 inclination of the earth's axis to the plane of its orbit, whe- 

 ther it happened suddenly or gradual^, may have caused 

 such a change in the direction of the oceanic and equatorial 

 waters of the ocean, as to make them desert some regions, 

 leaving them capable of subsidization and vegetation for the 



