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C! 



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Polt 



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 cot 



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 I us. 



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HtJTtONIAN tHEORY. 



i6y 



a highly indurated, but granulated quartz, is 

 found in feveral places in Scotland, in beds or 

 flrata, alternated with the common fchiitus of 

 the mountains. Remarkable inllances of this may 

 be feen on the north fide of the ferry of Bala- 

 chulifh, and again on the fea-fhore at Cullen. 

 At the latter, the ftrata are remarkably regular, 

 alternating with different fpecies of fchiftus. 



* 



At the former, the quartz is fo pure, that the 

 Itone has been miflaken for marble. 



r 



Thefe examples are perhaps fufficient ; but 

 I mult add, that in the micaceous and talcofe 

 fchifti themfelves, thin layers of fand are often 

 found, interpofed between the layers of mica or 

 talc. I have a fpecimen, from the fummit of 

 one of the higheft of the Grampian mountains, 

 where the thin plates, of a talcky or albeftine 

 fubltance, are feparatcd by layers ot a very fine 

 quartzy fand, not much confoli dated. 



The mountain from which it was brought, 

 confills of vertical fi;rata, much interfected by 

 quartz veins. It is impoffible to doubt, in 



this 

 fubft 



ft 



that the thin 



d th 



fmall 



gi 



2s of the one 

 of the other. 



were depofited together at the bottom of 



fea 



d th 



they 



were 



ke produced fro 



the degradation of rocks, more ancient than any 

 which now exift. 



L 4 



153- In 



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