264 W. UPHAM — GLACIAL LAKES IN CANADA. 



bulk of the accumulation of boulders and the rocky bluff on that side." 

 The ancient water-course thus described west of the portage is probably only 

 a few feet above Kenogami lake, having very nearly the same elevation as 

 the divide between the Missinaibi and Michipicoten rivers, some 150 miles 

 distant to the east. Both these low points of the water-shed were doubtless 

 occupied by rivers outflowing from glacial lakes on the north during the 

 recession of the ice-sheet. 



Missinaibi lake, near the head of Missinaibi river, the western branch of 

 the Moose river system, is about 1,020 feet above the sea. This lake " bears 

 S. 48° W., is twenty-four miles long, nearly straight, and varies from a half 

 to one and a half miles in width." ^ Close southwest of Missinaibi lake, in 

 the continuation of this glacial river-course, is Crooked lake, at an elevation 

 of about 1,038 feet. ^' It is eight and a half miles long, and averages less 

 than a quarter of a mile in width." Near the head of Crooked lake and 

 only a few feet above it is the Height of Land portage, approximately 1,042 

 feet above the sea; and thence descending toward Lake Superior the old 

 channel contains Dog lake, having a height of about 1,026 feet, and Mat- 

 tagaming or Mattawagaming lake, which according to the Canadian Pacific 

 railway survey is 1,025 feet above sea level. 



When the Kenogami, Missinaibi, and other glacial lakes of the James's 

 bay region became merged in one of great extent, rivalling Lake Agassiz, the 

 outlet of this confluent lake crossed the low water-shed south of the eastern 

 end of Lake Abittibi, passing to Lac des Quinze and Ottawa river. The 

 elevation of Lake Abittibi, according to observations of the Canadian Geo- 

 logical Survey, is about 857 feet above the sea, and the portage over the 

 water-shed rises only about 100 feet higher. Its present altitude is thus 

 nearly a hundred feet less than that of the Kenogami and Missinaibi out- 

 lets ; and it is probable that when the land was first uncovered from the 

 ice-sheet the Abittibi outlet was relatively lower than the others by a much 

 greater difference, and that with reference to the sea level it was much less 

 elevated than now. 



The Ottawa then received not only the overflow of a vast glacial lake in 

 the basin of James's and Hudson's bays, but also, as Gilbert has shown, the 

 discharge of Lakes Superior, Michigan and Huron, through Georgian bay 

 and by Lake Nipissing and the Mattawan river. Lake Nipissing is only 

 58 feet above Lake Huron, or 639 feet above the sea; a low water-shed of 

 gravel and sand divides it from Trout lake, tributary to the MattaAvan ; 

 and the junction of this river with the Ottawa, distant only 100 miles from 

 Georgian bay, is about 50 feet below that bay and lakes Huron and Mich- 

 igan. But on account of the northeastward depression of the upper St. 

 Lawrence and Ottawa basins when the ice disappeared, the avenue of dis- 



*GeoI. Survey of Canada, Report of Progress, 1875-76, p. 330. 



