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'v it 15 liidij 



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 - lilt 





HUTTONIAN THEORY. 



349 



/ 



ful inform 



What he fays on the fubjed 



f granite, is, in the main I believe juft ; b 



far too sreneral to aiithorife the 



b 



fi 



hich Mr Kirwan derives fr 



Dr Ash, for 



w ■ 



whofe judgment I have great refped, cannot, 

 I think, have meant, when he ufed the expref- 

 fion granitic rocks, to defcribe granite flrldly 

 fo called. He fays, in the pailage quoted by 

 Mr Kirwan, that '* from Galloway, Dumfries, 

 and Berwick, there is a chain of mountains, 

 commonly fchiftofe, but often alfo granitic." 

 Now, the fad is, that the great belt of primary 

 rock, here alluded to, which traverfes the foutli 

 of Scotland, conilfts of vertical fchiflus of va- 

 rious kinds ; but except in Galloway, and again 

 in Lammermuir, near Prieftlaw, it appears, as 

 already mentioned, to contain no granite what- 

 foever. If the German mineralogiil quoted by 



Mr Kirwan, when he fays that the Grampian 

 mountains coniift of micaceous limeilone, gneifs, 



I 



porphyry, argil) ite, and granite, alternat'ng with, 

 one another, means only to affirm that all thefe 

 Hones are found in the Grampians, he is certain- 

 ly in the right, and the catalogue might eafiljbe 

 enlarged ; but, if he either means to fay, that 

 thefe are nearly in equal abundance, or that the 

 granite is commonly found in llrata alternating 

 with other llrata, I mull fay, that thefe are pro- 

 portions 



