156 /. BURR TYRRELL 



the Keewatin glacier did not extend very far east of the present 

 eastern shore of Lake Winnipeg, and it is also probable that 

 throughout its advance there was a free drainage eastward into 

 Hudson Bay. 



Traces of the existence of the streams that flowed eastward 

 from the face or side of this glacier were found in several places 

 in the form of deep potholes or giant's kettles, excavated in the 

 summits or on the eastern slopes of knolls of granite, and gneiss 

 where they could not have been formed under present condi- 

 tions. At one place, on the south side of Berens River, several 

 of these potholes 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. The ten-foot hole was cleaned 

 out, and was found to contain a great many rounded pebbles, all 

 of Archaean rocks, some similar to the rocks of the surrounding 

 country, and others that had evidently been transported from a 

 distance. Both this and most of the other rocky hills where 

 potholes were seen, have been scored and scraped down 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. 



While a portion of the Keewatin glacier flowed southward in 

 the Winnipeg basin, another parallel glacial stream would seem 

 to have traveled southward between the Porcupine and Duck 

 mountains on the east, and the rising land now marked by the 

 Missouri Coteau on the west, both sides of this wide shallow 

 depression being now at elevations of about 2200 feet above the 

 sea. This glacial lobe probably extended southward into Dakota, 

 and at its greatest extension it coalesced with the Winnipeg 

 lobe over the summits of the Porcupine and Duck mountains, 

 but for long periods, doubtless when the glacier was both 

 advancing and retiring, the two lobes were more or less separated, 

 and an extensive interlobate moraine was deposited on the sum- 

 mits of these hills. The Missouri Coteau is also considered to 

 be the great moraine deposited along the west side of this lobe 

 of the Keewatin glacier. Whether the glacier extended west of 



