i6o 



ILLUSTRATIONS OF THE 



a 



146. After all, it may be afked, for what 

 purpofe is it that fo many incongruous and 

 ill-fupported hypothefes are thus piled on 

 one another? is it only to avoid afcribing the 



r 



carbonic and bituminous matter of coal to 

 fubftance in which we know with certainty that 

 fuch matter refides in great abundance, in order 

 to derive it from other fubftances, in which a 

 fubtle analyfis has (hewn, that it exifts in^a very 

 fmall proportion ? Such reafoning is fo great a 

 trefpafs on every principle of common fenfe, not 

 to fay of found philofophy, that, to beftow any- 

 time on the refutation of it, is, in fome degree, 

 to fall under the fame cenfure. 



Note hi. § 7. 



Primitive mountains. 



147. The enumeration of the different kinds 

 of primary fchiilus, at § 7., is not propofed as 

 at all complete. It will be lefs defective, how- 

 ever, if we add to it talcoje JchiJluSy and lapis- 

 ollaris or potjlone *. 



148. The rocks called here by the name of 



primary, were firft diftinguifhed, as forming the 



bafis 



* Kirwan's Mineralogy, vol, i. p. 155 



