654 GEORGE W. BAIN 



Garnet Rock Garnet Garnet 

 Per Cent 



SiOz 53 • lo 



Al A 



Fe A 



FeO 



MnO 



CaO 



MgO 



Na,0 



K.O 



H^O 



100.05 99-98 100.19 



In addition to garnet the rock contains numerous grains of 

 magnetite and stringers of clear quartz. Feldspars are also 

 abundant. 



THE BIOTITE GNEISS 



When the garnet zone is followed along the strike for any 

 distance it passes into a biotite gneiss. Thin sections of this gneiss 

 were examined and the rock was seen to contain about: 



Per Cent 



Biotite 15 



Quartz 25 



Chlorite 15 



Orthoclase 12 



Andesine 15 



Almandite .' 5 



Sillimanite 3 



Carbonates 3 



Sericite 2 



The garnet is heavily fractured and elongated in the plane 

 of schistosity. Along these fractures it has altered to a green 

 chlorite which itself is recrystalhzing to form biotite. The silli- 

 manite exhibits a change similar to that taking place in the 

 garnet. 



