DOMAIN I. SIDEROUS. 



basalt is only found on summits, and it is evi- 

 dently perceived by the correspondence of the 

 beds, that all these summits were parts of one 

 and the same bed, which spread over all the 

 country : now, that is not the nature of volcanic 

 deposits ; they form currents, which take a cer- 

 tain direction, and no similar examples of such 

 vast deposits are known, but among rocks pro- 

 duced by water, and particularly among strati- 

 form rocks. 



"11. Basalt has no appearance of fusion; 

 heated in a furnace it melts to glass. It is true, 

 that from Hall's experiments, a stony substance 

 has been obtained ; and that may very well hap- 

 pen, since nature produces it in burning vol- 

 canoes. But these cases are very rare, and Hall 

 has justly observed, that in his experiments this 

 appearance depended on the management of the 

 cooling : but it must then be supposed, that this 

 circumstance is always met with in the volcanic 

 eruptions, which are supposed to have produced 

 the mountains of trap. 



" 12. The prismatic division of basalt has 

 been attributed to the water of the sea, which 

 they say then covered all the region upon which 

 these lavas have run: that is possible; but this 

 accelerated refrigeration should, according to 

 Hall's experiments, give the lavas a vitreous 



