H. F. Griggs — Divided Lakes in Western Minnesota. 389 



bottom of the pond. But its front slope (fig. 2) exhibits the 

 typical features of an ice rampart. It is built of gravel with 

 occasional bowlders of large size. It is very steep and in places 

 the ice has shoved up over the bowlder front and cut into the 

 turf of the top. 



Detroit Lake on the line of the Northern Pacific Railway is 

 the most accessible example of a large lake with such barriers. 

 In this case the process of division is not complete and the 

 two ramparts form a pair of slender points stretching out from 

 the opposite shores. A view of the southern point is shown in 



Fig. 1. 



Fig. 1. A dividing rampart, Lake Pelican. 



figure 3. It is remarkable in its extreme narrowness. Though 

 nearly a mile long, it is hardly more than one hundred feet 

 wide at the widest point and the tip is so sharp that the 

 extremity is hardly wide enough for the feet of the observer. 

 The opposite point reaching out from the northern shore is 

 very similar but is not so long. The two are connected by a 

 submerged bar over which the water is so shallow that boats 

 can cross only in a narrow passage in the center. But there is 

 no channel across and the passage is simply the lowest point in 

 the continuous ridge. In character this point is very different 

 from such ramparts as that shown in figure 1. It is built of 

 sand and gravel from which bowlders are almost absent. It is 

 nowhere high or steep-sided like the bowlder rampart, but rises 

 scarcely three feet above water level. 



In many respects this point resembles sand spits formed by 

 water work. The fine materials of which it is built and its 



