8 



at the north the end of the lake is reached by the farthest 

 north extent in this district of the Huronian strata. This 

 forms a narrow rocky neck, having the waters o^ the Lake of 

 the Woods on the southern side and on the noi th the begin- 

 ning of the Winnipeg River, known as Dailington Bay. This 

 is at a level considerably lower than that of the lake. 



Between the western and northern peninsulas a long, nar- 

 row strait runs through the Huronian strata. It is called 

 Ptarmigan Bay ; this again leads by passing Ash Rapids and 

 through the narrow Shoal Lake channel to Shoal Lake, a 

 body of water somewhat higher than Lake of the Woods. 

 Shoal Lake is triangular in shape with a greatest north and 

 south measurement of thirteen and a half miles, and a greatest 

 breadth of seventeen miles. This haa as we shall see become 

 famous as having mineral deposits of value. An eastern ex- 

 tension of the lake, named Whitefish Bay, shut in by the base 

 of the Grande Presqu'ile, lies almost entirely in the Laurentian 

 basin, though its northern and eastern shores are Huronian 

 and contain mineral deposits. 



ROCKS. 



1. The rocks of the Laurentian formation of the soutli 

 end of the lake are, as has been said, hard gneissoid rocks. 



2. The softer schist rocks of the north end of the lake 

 are much more varied in species. Like the Laurentian they 

 are all stratified rocks, which have gone through the process 

 of metamorpliism by heat. If there ever were any fossils in 

 them all traces of these have been removed. Near Rat Port- 

 age these rocks are slaty quartzites and siliceous schists. 

 The greenish rock known as chloritic rock of hornblende and 

 feldspar is found at different points. Talcoid schists and 

 siliceous diorites are come upon, but iti general the rocks of 

 the whole series are made up of coarse laminated schists. The 

 arrangement of the rocks made by Lawson is : L Mica schist 

 on the surface ; 2. Agglomerate schist below this ; and, 

 3. Hornblende schist lowest down, resting on the Laurentian 

 gneiss. The thickness of these beds varies much ; but an 



