236 THE GLACIAL LAKE AGASSIZ. 



thus remarkably changed from their original horizontality. It is clearly 

 shown here that the uplifting was not uniformly proportionate and regular 

 for the whole area of Lake Agassiz. The chief movements of elevation of 

 its southern and central part, as far to the north as Gladstone, seem not to 

 have extended farther, at least in their full proportion. The district next 

 to the north along an extent of 120 miles to Pine, Duck, and Swan rivers, 

 at the north end of Duck Mountain, was perhaps only so far disturbed by 

 these movements as was necessitated to connect the rise of the country 

 on the latitude of Gladstone with the continuing condition of maximum 

 subsidence on the latitude of the lower part of the Saskatchewan and 

 the north end of Lake Winnipeg. But there ensued in this district, after the 

 date of the Campbell beach, a great differential elevation, giving to these 

 late shore-lines two to three times more northward ascent than that of 

 the Herman beach from Lake Traverse to Gladstone; and the total change 

 in level of the highest observed beach, probably representing the upi)er 

 Norcross stage, situated at Pine River, on latitude 51° 50' to 52° north, is 

 approximateh" 400 feet as compared with this shore-line at Lake Traverse, 

 about 420 miles distant to the south. Nearly the whole uplift of the 

 northern part of the basin was accomplished, however, while the ice-sheet 

 was still a ban-ier of the lake, for the Niverville beach at the Grand Rapids 

 of the Saskatchewan is only slightly higher than on the Red River, 250 

 miles to the south. 



Review of the epeirogenic uplifting. — After the recession of the ice from 

 its \'icinity, the mouth of Lake Agassiz by the River Warren was uphfted 

 apparently at least 50 or 75 feet, and perhaps as much as 90 feet, by several 

 small stages of elevation, separated by comparatively long pauses. Thence 

 to the latitude of Gladstone, in a distance of 300 miles northward, such 

 small uplifts, increasing in number and in aggregate vertical amount from 

 south to north, raised the lake basin in southern Manitoba not less than 200 

 feet; and, in combination with the fall of the lake level northward, due to 

 decreasing ice attraction, the change in level was 265 feet. To these figures 

 we must add the uplift of the Lake Traverse region, which was probably 

 between 50 and 100 feet, to obtain the total epeirogenic elevation at 

 Gladstone. Later ei)eirogenic movements of the same kind raised a more 



