BERING SEA 



a highly inclined slate, and the shaping of the surface has 

 been wholly by erosion. Except at the coast, the rocks 

 are concealed by tundra. This spongy growth obstructs 

 the flow of water, so 

 that streams are rare ; 

 but we landed at one 

 of these rare streams 

 and had a view of its 

 valley (fig. 91). The 

 valley is evidently 

 one of mature de- 

 velopment, and its 

 profiles are perfectly 

 adjusted to the associated lines of drainage. The divides 

 are broadly rounded, but the rounding is that characteristic 

 of inter-stream summits where the vegetal mat is close, 

 and is distinctively non-glacial. The bed-rock here has 

 the same physical character as that in the Kadiak region, 

 but the topographic aspect is altogether different. About 



FIG. 90. 



UNGLACIATED KNOB ON ST. MATTHEW 

 ISLAND. 





FIG. 91. STREAM-GRADED VALLEY NEAR PORT CLARENCE. 



Kadiak the hills have moutonnee forms, the hills and hol- 

 lows have a dominant trend, and the drainage is youthful. 

 At the Port Clarence locality the topography does not 



