ALMANDITE AND ITS SIGNIFICANCE 



651 



wm 



ScaU \ inch to I Mile 



LQ>,r«ntloa Gn 



Gronite Porphyry 

 &r anile ond. Syeni-le 



Skcrn flochs 

 Crystalline Lifneslonc 



Pleistocene 



Fig. I. — Map of the Grenville Series and related rocks of Chatham Township. 



age, but mainly large intrusive batholiths of granite. Glacial debris 

 of the Pleistocene ice sheet is strewn over the surface. 



J Lake deposits 



\ Ground moraine 



' Trap and microgranite 

 Granite porphyry 



Keewenawan " Granite and syenite 



Granodiorite 

 , Diabase 



{Granite 

 Aegerite granite dykes 

 Peridotite and pyroxenite 

 Grenville Series Limestone 



In this complex only the Grenville series and the Laurentian granite 

 are of interest in this paper. 



THE GRENVILLE LIMESTONE 



The Grenville limestone is a blue, coarsely crystalline limestone 

 composed of about i per cent of dolomite, 15 per cent of wollastonite 



