rifp: GKXEsrs of lake agass/z 813 



the eastern slopes of knolls of granite and gneiss, where they 

 could not have been formed by the present streams or by others, 

 like them, flowing westward. At one place, on the south side of 

 Bcrens River, several of these pot-holes occur on the east side of 

 a granite knoll, one of them, at least, being ten feet in depth, 

 and about thirty inches in diameter from top to bottom. On the 

 same side of the knoll, facing up the present stream, was a well- 

 marked water-worn groove, leading down to a shallow pot-hole 

 at the foot of the hill. The ten-foot hole was cleaned out and 

 was found to contain a great number of well-rounded pebbles, 

 all of Archaean rocks, some similar to the rocks of the surround- 

 ing country and others that had evidently been transported 

 from a distance. Both this and the other rocky hills where the 

 pot-holes were seen have been eroded and scored by the later 

 glacier from the east, the outer sides of some of the holes 

 having been cut away, leaving rounded niches in the faces of 

 the smooth hillsides. 



After occupying the basin of Lake Winnipeg and the Red 

 River Valley for an uncertain but doubtless long period of time, 

 the Keewatin glacier began gradually to retire. As it retired a 

 portion of the Laurentide glacier, which in the meantime had 

 been accumulating in the country farther east, perhaps in the 

 high land of the Labrador peninsula, gradually advanced. The 

 Keewatin glacier seems to have retired northward well into 

 Manitoba, and possibly even beyond the northern limit of that 

 province, before it was joined by the eastern glacier. When 

 they united the water was ponded between the fronts of the two 

 glaciers to the north and east, and the high land to the south 

 and west. Thus Lake Agassiz had its beginning. Its waters 

 rapidly rose until they overflowed southward into the valley of 

 the Mississippi and then gradually declined as the river Warren 

 deepened its channel. 



After the union of the two glaciers the Keewatin glacier may 

 ha\c remained stationary for a considerable period, during which 

 time the strong ridge extending from Long Point westward 

 between Cedar and Winnipegosis lakes and beyond, apparently 



