POSSIBLE BARRIEB OP LAKE AGASSIZ. 303 



what has already been said on this subject. It has been assumed by some 

 geologists that, owing to the supposed lowness of the land, the front of a very 

 wide glacier would be requisite in order that the water of this lake might have 

 been sustained on the east; but no actual evidence has been offered, except 

 by myself, that any glacier ever existed in that quarter. Although it would 

 appear that the ice-sheet did at one time push its way from the bed of 

 Hudson's bay, or even from the high lands of the Labrador peninsula to 

 the east of it, across the intervening country, this agency may not have been 

 necessary to account for the existence of the lake. The gap which would 

 require to be stopped in order to dam up the water and cause it to spread 

 over the shallow basin of Lake Agassiz is much narrower than is commonly 

 imagined. Without supposing any change of levels, the water-shed between 

 Lake Winnipeg and Hudson's bay is more than sufficiently high to retain 

 the water till it comes within a very short distance of Nelson river. Then 

 on the northwest side of this great stream the land rises rapidly below the 

 junction of Burntwood river to a height of at least 500 feet above the main 

 stream, and the Churchill flows in a valley much more elevated than that of 

 the Nelson. 



Great quantities of moraine matter are deposited on the western slope of 

 Hudson's bay on all the routes which I have followed in travelling to it from 

 the interior. It forms hills and ridges, through which the rivers have cut 

 their way. Hill river, on the travelled route between Lake Winnipeg and 

 York Factory, is so called from Brassy hill, a steep, conical mound of earth 

 in the line of a great moraine, which rises to a height of 390 feet above the 

 water at its base, where it is intersected by the river. This is, perhaps, 

 higher than the level of Lake Winnipeg. From the top of this hill about 

 twenty moraine lakes may be counted. 



This paper is already too loug, or many interesting facts might be given 

 in reference to the intersection on other rivers of what may be the continua- 

 tion of this moraine. But, judging from what I have seen on my own ex- 

 plorations and from what I have been told by local travellers, I may simply 

 say it seems probable that a great terminal moraine may be traced along 

 the western slope of Hudson's bay at a considerable distance inland and with 

 an elevation of several hundred feet above the present level of its water. It 

 is possible that at one time part of this moraine choked up the valley of 

 . Nelson river and flooded back the water of the Winnipeg basin so as to form 

 Lake Agassiz. This would be rendered all the easier if the continent were 

 slightly more elevated to the eastward than it is at present, and there is 

 much reason for believing that it was so. The well-marked beaches of 

 Lake Agassiz show that its waters were stationary at certain levels for a con- 

 siderable time, wdiich could scarcely be possible if its outlet were through or 



XL— Bull. Geol. Soc. Am., Vol. 1, 1889. 



