240 T. C. CHAMBERLIN 



The back of Bowdoin glacier is marked by an interesting 

 medial moraine that takes its rise far up toward its junction with 

 the main ice-cap, Fig. 68. I did not see its origin, but Lieu- 

 tenant Peary informed me that it came to the surface from 

 beneath the ice at a point north of the north nunatak, but south 

 of the descent of the ice from the main plateau. On account of 

 this he could not be certain whether it was derived from a 

 nunatak that lies still farther north on the border of the main 

 plateau, or from some concealed embossment. Undoubtedly 

 the material was picked up from a prommence on or near the 

 edge of the plateau. The debris is so thinly spread that it 

 catches the sunlight and by conversion and conduction makes 

 its heat available to the ice. As a result the moraine is sunken 

 ten or fifteen feet below the surrounding surface. In breadth 

 and form it is not unlike a depressed street strewn with coarse 

 debris. On one ■ side of it a stream has cut a notable trench 

 through which a considerable body of water flowed during the 

 warm days of August. Fig. 68 illustrates the moraine and its 

 depressed condition, as also the channel on the west side. The 

 latter terminates in a moulin at the right-hand lower corner of 

 the illustration. The moraine is also illustrated in the general 

 transverse view of the glacier shown in Fig. 64. 



T. C. Chamberlin. 



