DOMAIN VII. COMPOSITE. 



it has already been explained that felspar 

 and quartz, united with siderite or mica, 

 or with both, are indispensable attributes 

 of that substance. The micg, may pass to 

 micarel, or even steatite; and the appear- 

 ance of schorl or garnets, not to mention 

 the gems, cannot be considered as altering 

 the nature of the substance. 



But the name granite has, on the con- 

 trary, by Gmelin and many other writers, 

 been extended to almost every aggregation 

 that can be conceived. Such heteroge- 

 neous aggregations are here arranged un- 

 der the name of Composite Rocks ; while 

 some, as that beautiful rock called the Cor- 

 sican granitel, are placed among the Ano- 

 malous, as departing from the usual rules 

 observed by nature. 



substantial The latter six great divisions of the rocks, 

 being derived, not from the nature of the 

 substances themselves, but from accidences 

 or circumstances, may be called ACCI- 

 DENTIAL, or circumstantial; while the 

 former divisions are SUBSTANTIAL. The 

 phemical Mode therefore, so essential in 



