«<3 



Of this important fact, which Mr. Whitehurst quotes 

 with triumph, Dr. Hamilton takes liot the least notice^ 

 for it would have been very awkward, when demonstrat- 

 ing the impossibility, of basalt pillars being formed m 

 cm-rents of lava, to have mentioned an instance, where 

 Mr. St. Fond, Avhom he admires so much, had found them 

 in an actual current. 



As to the argument, drawn from -^tna and Mont de 

 la Coupe, resting on columnar bases, I must observe, that, 

 from the accounts, given by Mr. St. Fond and Mr. Dolo- 

 mieu, of these mountains, it appears, that the whole 

 country, surrounding the latter, was formed of columnar 

 basalt; and, as to iEtna, Dr. Hamilton himself quotes Mr. 

 Dolomieu, to shew, that, in its whole contour, basalt pillai. 

 were found, and that they formed a circular cmcture aboyt 

 it, from twelve to eighteen hundred feet high. 



Now, if we adopt Dr. Hamilton's theory, we must ad- 

 mit, that the whole country, round these volcanos, was 

 once included in their craters r a concession, which the 

 reader will not readily make. 



Besides, Dr. Hamilton ascribes the formation of these 

 prisms to crystallization; a principle totally different frojn 

 that adopted by Mr. Desmarest and Mr St. Fond; who 

 •/(make the operations, by which they were formed, ana- 

 logous to desiccation; and, like it, they seem to require 

 exposure to the external air: and Mr. Kirwan has clearly 

 proved, that basalt prisms do not acquire their xegular 

 ^ ,, forms 



VOL. X. 



