THE INTERGLACIAL GORGE PROBLEM 



145 



is lower than the low rock outcrop which extends along the 

 eastern edo^e of this channel. We still have left Gora^e No. 

 3 and Gorge No. 4. These gorges may possibly belong together, 

 though that is by no means certain. By taking the low ridge of 

 rock east of the stream as one edge of Gorge No. 4, we can 

 reduce its width to 75 yards, but it is still nearly three times as 



Fig. 4. — A view in the drift-filled gorge of Ten Mile Creek. 



wide as Gorge No. 3, and it is also more than 10 feet deeper. 

 If, however, we assume that there was a fall somewhere between 

 the two gorges, it would account for the difference in depth ; 

 but this assumption does not explain the difference in width. 



Downstream extension of these gorges. — All these gorges must 

 have entered the inlet through the broad gorge below the 

 reservoir, which lies north of the postglacial gorge, for the rock- 

 wall of the Inlet Valley is continuous for two miles on either 

 side of the drift-filled gorge, except where there are postglacial 

 trenches. It is possible that there is a local divergence of the small 



