( 217 ) 



bafe — Black mica one of the component 

 parts of this granite, which has the pro* 

 pcrty of being attraSfed like iron by the 

 mag?iet., a property poffeffed likewfe by the 

 other micas of the Kuganean mountains — 

 The micas of the primitive granites defli- 

 tute of this property y but capable of receiv- 

 ing it by the action offre — This important 

 faflfurnifhes a clear proof of the volcani- 

 %ation of the Kuganean mountains — Nodo" 

 fities of quartz contained in this granitons 

 lava, probably produced by filtration pofe- 

 rior to ignition — The fame obfervable of 

 fome fldoerlaceous nodofities included in it — 

 Thefhoerls of the Kuganean mountains aB 

 oil the magnetic 7ieedle, like thofe of other 

 volcanic coimtries, and in that differ from 

 thofe which are not volcanic — Calcareous 

 carbonates intermixed with the lavas of 

 the Kuganean mountains — Klints frequent" 

 ly found among thefe calcareous carbonates^ 

 'which prefent the mofl fpeciotis appearance 

 of the change of lime into flex — Proof by 

 chemical analyfis, that it is not neceffary to 

 have recourfe to any fuch change to explaiti 



this 



