138 SA LI SB URY A ND A TWO OD 



From this point eastward for about three miles the ridge is 

 clearly defined, the slopes about equal on either side, and the 

 crest as nearly even as the typography of the underlying surface 

 permits. The topographic relations in this part of the course 

 are shown in Fig. 5. 



At e (Fig. 2) this marginal ridge attains its maximum eleva- 

 tion, 1620 feet. Here again, the ice having surmounted this 

 great elevation, the greatest of the region, was unable to move 

 forward down the slope, although it had had energy enough to 

 climb fully 300 feet in the last mile of its advance. 



At this great elevation, the ridge turns sharply to the north- 

 west at an angle of more than 90°. Following this direction for 

 little more than half a mile, it turns to the west. At some points 

 in this vicinity the ridge assumes the normal morainic habit, but 

 this is true for short distances only. Further west, at/, it turns 

 abruptly to the northeast and is sharply defined. It here loops 

 about a narrow area less than sixty rods wide, and over half a mile 

 in length, the sharpest loop in its whole course. The driftless 

 tract enclosed by the arms of this loop is lower than the drift 

 ridge on either hand. The ice on either side would need to have 

 advanced no more than thirty rods to have covered the whole 

 of it. 



From the minor loop just mentioned, the marginal ridge is 

 continued westward, being well developed for about a mile and 

 a half. At this point the moraine swings south to the north end 

 of Devil's Lake, loses the unique marginal ridge which has char- 

 acterized its outer edge across the quartzite range for so many 

 miles, and assumes the topography normal to terminal moraines. 

 At no other point in the United States, so far as known to the 

 writers, is there so sharply marked a marginal ridge associated 

 with the terminal moraine, for so long a distance. 



From Fig. i it will be seen that the moraine as a whole makes 

 a great loop to the eastward in crossing the quartzite range. 

 From the detailed description just given of the course of the 

 marginal ridge, it will be seen that it has three distinct loops ; 

 one on the Devil's Nose (west of b, Fig. 2) ; one on the main 



