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muft have occurred in fuch an immenfe body of an heterogeneous 

 fluid, nor perfedlly pure by reafon of its affinity to argil and 

 calx. Next to this felfpar, containing a fmaller proportion of filex 

 and a larger of the other earths, proportions which, from their 

 eafy fufibility, alfo appear to exhibit the maximum of attraction of 

 thefe earths to each other when filex and argill prevail, muft have 

 cryftallized next, and laftly the mica, a flone in which the pro- 

 portion of filex to argil is ftill fmaller. The portion of water 

 difengaged from thefe earths gradually afcended and made room 

 for new fhoots, which attaining the foregoing before they were 

 perfcdly hardened adhered to them clofely, and thus at lafl: vaft 

 uniform blocks were formed ; where the fhoots had not attained a 

 certain degree of hardnefs, or the fofter ingredient, viz. the mica 

 abounded, the gneifs was formed ; and where the proportions re- 

 quifite to form felfpar were deficient, the other granitic ingredi- 

 ents being prefent, fhiftofe mica was formed. Hence we may 

 underftand how it has happened that gneifs fiiould fometimes be 

 found in granite*, and fometimes mafiTes of granite in the midft 

 of gneifs, and why in mountains, granite, gneifs and fhiftofe mica 

 frequently alternate with each other, Charpent. 390. 



As the fluid from wliich thefe cryftallized granitic mafTes fub- 

 fided was of the moft heterogeneous kind it is not to be won- 

 dered at that various metallic fubftances, and particularly iron, 

 and even fome traces of carbon and plumbago, fhould fometimes 

 occur in them. 2 Saufs. 451. 2 Bergm. Jour. 1790. 532. 



H h 2 In. 



» Werner kurze ClaiEf. 9, io.~ 



