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«i 



III 



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HUTTONIAN THEORY. 



The foffil now defined exifts, like whinllone 

 and porphyry, both in maffes and in veitis^ 

 though mod frequently in the former, 

 like them unftratified in 



It 



IS 



Its texture, c 



ind 



IS re- 



garded here, as being alfo unftratified in its out- 

 ward fl:rud:ure*. One ingredient which is eHha^ 

 tial to granite, namely, quartz, is not contained 

 inwhinflone; and this circumfiiance ferves to 

 diftinguifh thefe genera from one another^ 

 though, in other refpeds, they feem to be uni- 

 ted by a chain of infenfible gradations, from the 



F 2 



mofl: 



r 



I" 



It 



* Tliofe rocks that conlift of the ingredients here enu- 

 merated, if thej have at the fame time a fchiflofe tex- 

 ture, or a difpoiltion into layers, are properly diftin- 

 guiflied from granite, and called Gneifs, or Granitic 

 Schiflus. But it has been queftioned whether a ftone 



)ofed of thefe iuCTedients, and delli- 



com 



tute of a fchillofe texture, but yet divided into large 



rm 



Dr 



y 



fuch proportion of the mineral kingdom, as to entitle it 

 to particular conlideration, in the general fpeculations of 



ology. 

 Whetl 



m 



quire to be farther confidered : this, however, is certain^; 



onformable to it, com 



great proportion of what are ufually called the granite 



niountams. 



Not 



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