83 

 GRANITE ISLAND. 



The Pre-Cambrian quartzites are exposed on many of 

 the islands north of Manitoulin, and present interesting 

 contacts with the low-lying Palseozoic strata. Extensive 

 masses of granite have invaded the quartzites and are now 

 exposed on several of the small islands between Mani oulin 

 and the mainland. The coarse red granite of Granite 



Residual Lowville limestone in cavities in granite. 

 Ontario. 



Granite Island, Lake Huron, 



island presents interesting contact phenomena with the 

 quartzites, but it is particularly worthy of note on account 

 of the occurrence of sedimentary limestone in kettle-like 

 hollows at an elevation of 50 or 60 feet (15 to 18 m.) above 

 the water of the lake. Fossiliferous strata of Lowville age 

 occur along the north shore of the island at water level. 

 These beds show a basal arkose covered by limestone 

 layers with a strong cephalopod fauna represented for the 

 35066—6! 



