244 ASSINNIBOINE AND SASKATCHEWAN EXPEDITION. 



water communication, possessing many singular geogra- 

 phical outlines, arising from the geological features of the 

 country. 



Both Lake Superior and Lake Winnipeg belong to the 

 same geological basin, and are excavated in its rim, the 

 low Laurentide Mountains separating the great northern 

 basin of fossiliferous rocks from it. 



The canoe routes between Lake Superior and Lake 

 Winnipeg form, therefore, two chords on the edge of the 

 gneissoid and granitic boundary dividing these geological 

 basins, and while the general trend of this part of the 

 Laurentide Mountains is geographically north-west, the 

 direction of the undulations, by which it is intersected, 

 is generally north-east and south-west, or at right angles 

 to the former. This disposition is best developed east 

 of Eainy Lake, and on the Pigeon Eiver route, where 

 the agency of the elevating force appears to have acted 

 with greater constancy and uniformity than on the more 

 northern canoe route. The outbursts on the southern 

 route, as well as on the south shore of Lake Superior, 

 are also considerably higher, and the lakes and lake straits 

 more symmetrically arranged. 



An inspection of the geographical map will show that 

 the longest axis of nearly all the smaller lakes in the 

 region under review is from N.E. to S.W. 



A range of greenstone ridges, forming an anticlinal axis, 

 begins at the Great Bend of the St. Louis Eiver, and runs 

 in a direction N. 30° E. towards the sources of Arrow 

 Eiver and Mountain Lake. The systems of valleys and 

 ridges, resulting from the direction in which the elevating 

 forces have acted in the region about the western ex- 

 tremity of Lake Superior, have been ably discussed by 

 Dr. Norwood.* 



* Owen's Eeport of a Geological Survey of Wisconsin, &c. 



