418 C. K. LEITH 



As to the origin of these rocks, the thick unstratified and brec- 

 ciated graywacke or arkose may represent consolidated masses of 

 volcanic ashes or mud with stones, which were thrown upon the land 

 or into shallow water, while the stratified varieties may have consisted 

 of similar ejectamenta, thrown into deeper water where they became 

 arranged into layers as we find them. Some of these rocks, whether 

 stratified or otherwise, may represent volcanic products which were 

 originally thrown into the sea in a molten or heated condition and 

 became broken up and almost completely disintegrated. 



A study of the different phases of the graywackes and their 

 associated rocks in this region would appear to prove that the former 

 constituted the crude material from which both the quartzites and 

 clay-slates were derived by the modifying and separating action of 

 water. Again, by the action of time, pressure, heat, and other 

 metamorphosing agents upon different varieties of graywacke, some of 

 our granites, syenites, gneisses, and possibly other crystalline rocks, 

 were probably formed. 



Solid and slaty argyllites are found along Long Lake, an expansion 

 of the Whitefish River, and slate conglomerates occur on both sides of 

 Bear Lake and between Cat and Leech lakes. However, these rocks 

 do not form a large proportion of the Huronian series in this district. 



Impure magnesian limestones occur in the northern part of the 

 Bay of Islands, in the northwest part of the township of Rutherford, 

 and north of the area of the sheet near Lake Panache. 



Between the Huronian rocks on the north and the Laurentian rocks 

 on the southeast there is a belt of red granite, the Killarney belt, 

 running from Badgely Island to Three-mile Lake. This granite is 

 apparently of eruptive origin, and of later age than the quartzites. All 

 along the line of contact with the Huronian the rocks give evidence 

 of great disturbance. Huge portions, as well as many of moderate 

 size, have been separated from both sides and have been mingled 

 together and intermixed with finer debris, all being cemented into a 

 coarse breccia. 



The southeastern side of the Killarney belt of granite rests against 

 the Laurentian gneiss, except in the interval from the southern point 

 of George Island to the entrance of Collins Inlet, where a narrow belt 

 of partially altered, fine grained, brittle, red and sometimes gray 

 quartzite intervenes between the granite and the water of Georgian 

 Bay. Further northeastward, or where the granite of the Killarney 



