GLACIAL STUDIES IN GREENLAND 



239 



mum displacement of two adjacent layers, however, exceeded 

 two feet. The adjacent faces appeared to be very distinctly 

 fluted by the movement. Skepticism with reference to the 

 interpretation of the fluting was subsequently raised on the 



Fig. 68. Sunken medial moraine on the back of Bowdoin glacier ; seen from a 

 point near the moulin looking northerly. The ice motion is toward the foreground. 

 The width of the moraine is about four rods and its depth below the general surface ten 

 or fifteen feet. The stream's trench is shown at the left. It falls into the moulin at the 

 lower right-hand corner. Glimpses of the main ice-cap are caught beyond the 

 heights. 



ground that it might perhaps be due to unequal melting by 

 water trickling down the face of the ice, but, as elsewhere noted, 

 in one instance at least, the debris in the junction plane was cor- 

 rugated. It was noted here that a shearing plane was offset ; 

 that is, the shearing plane passed from the contact between two 

 given planes to a similar contact between two planes below. 

 The offset was downward and to the right or up-stream side. 

 The overthrust was about six inches and the offsets, two of 

 which were sketched, about ciijht inches. 



