DOMAIN II. SILICEOUS. 209 



MODE IX. GRANITOID. 



Many rocks, inaccurately classed among gra- 

 nites, are reserved for the Composite Domain. 

 Such alone as perfectly resemble granite, but 

 are of a very different modification, are here 

 styled granitoids; and this denomination pre- 

 sents three different structures. 



STRUCTURE I. CALCAREOUS GRANITE. 



In this rock lime-stone supplies the place of fel- 

 spar. This substance was first mentioned by 

 Kalm, as forming chains of mountains in Canada. 

 It was afterwards described by Saussure. Wer- 

 ner told me that he regarded it as a truly primi- 

 tive lime-stone. 



Calcareous granite, from the mountains of Ca- 

 nada. 



The same, from the vicinity of Mount Cenis. 

 But in the Alps it more commonly assumes the 

 form of gneiss, as at Roth Horn, Mont Cervin, &c. 



Reddish calcareous granite, or primitive lime- 

 stone with quartz and mica, from Scotland*. 



* The Journ. de Ph. 17Q1, mentions a calcareous granitoid, the 

 lime-stone or spar being in globules of an oval form, with crystallised 

 facetts, and compressed horizontally. 



VOL. I. P 



