Chap. 16.] [ 101 ] vr , 



CHAP. XVI. 



COMPOUND EARTHS. 



Definition of this Gtnus* Various compound Stones. 



IN a ftricl: fenfe all earths and flones, as they exift 

 in nature, may be denominated compound, as 

 there are none which are wholly fimpje. By com- 

 pound earths, however, is here meant fuch as are 

 formed of two or more kinds of ftony matter, and 

 which in general conftitute a mafs of an heterogeneous 

 appearance. In treating of thefe fubftances, the ar- 

 rangement of M. Daubenton appears the moft perfeft 

 and commodious. 



Mixed Stones^ 



OF TWO GENERA. 



Quartz and fcintillating fpar - Granitin. 

 Quartz and fchirl - GranUellg*. 



Quartz and fteatites Quartzofe fteatltes. 



Quartz and mica - - Micaceous quartz. 



Tranfparent quartz and mica - Micaceous ciyftal. 



* i Garnet on, grit 



Quartz in grit and gem ftone - J n ftone : 



^- S z Garnet in grit 



(_ ftone. 



Quartz in grit and mica - - Micaceous grit. 

 Quartz in grit and calcareous V i Cryftallized grit, 

 matter - - - - 1 2 Grit in ftalaaites. 



. - , , in. Vfandy and filiceous 



Quartz in fand and opake ftone | breccias. 



H 3 Quartz 



