( 2o3 } 



from the injuries of the fea, by the extCf-^ 

 nal ftrata, muft ftill preferve their prifmatie 

 configuration, of v/hich, however, no traces 

 remain. We muft, therefore, conclude 

 that innumerable lavas may fall into the 

 fea, without having their external appear- 

 ance in the leaft changed by the fudden 

 congelation VN^hich then takes place. 



That the prifmatie configuration of lavas 

 is not always the effedl of their immerfion 

 in the waters of the fea, likewife appears 

 from many of them taking the fame form 

 in the air ; of which v/e have a diftin- 

 guifhed example in the crater of Vulcano. 

 Here, certainly, we cannot fuppofe any in- 

 tervention of the waters of the fea. Si- 

 milar obfervations have been made on 

 Mount Etna by the Chevalier Gioeni. 

 " I have obferved,'^ fays he, in the work 

 before cited, " bafaltic columns, at the 

 " fummit of Etna, and nearly on a level 

 " with the bafe of its vaft crater, v^^here 

 *' there is certainly no probability of the 

 " fea ever having reached j and I have 



" frequently 



