258 R. S. TARR — FORMER EXTENSION OP CORNELL GLACIER. 



moraine stretching seaward, the sole blotch upon the otherwise univer- 

 sally white surface. Here and there the ice rises in the form of mounds 

 several hundred yards in diameter and cracked upon the surface. These 

 appear to mark the site of hills now buried beneath the ice, but near 

 enough to the surface to produce an irregularity. To the westward of 

 mount Schurman there is a mound of this sort, showing an elevated 

 crevassed ice-surface when seen from the east, but proving the existence 

 of the peak by the presence of land, which may be seen from the west or 

 water side. This is a nunatak which is just now beginning to appear 

 (see plate 28). 



At present the Cornell glacier comes to the land at the base of the 

 Upper Nugsuak peninsula, presenting either a steep slope or else a pre- 

 cipitous wall of ice, which is usually faced by a moraine embankment. 

 West of it rises the land of the peninsula to the height of 1,000 or 2,000 

 feet above its present marginal surface. Turned to the northwestward 

 and southwestward by this highland ridge, the ice creeps into the val- 

 leys forming the WyckofT and Cornell glaciers ; hence along this margin 

 the ice movement is diagonal to that of the main ice-cap and the valley 

 glacier tongues. 



The moraine that is built along this land margin is made of ver}^ 

 bouldery boulder-clay. The rock fragments are mainly gneiss, but in 

 the moraine are found numerous pebbles and large boulders of a por- 

 ph}^ritic red granite, of slate, and of quartzite. Somewhere to the east- 

 ward of the margin of the ice there must be a source for these materials, 

 and it is mainly from a study of their distribution that the former glacia- 

 tion of the peninsula was determined. 



EVIDENCES OF FORMER ICE INVASION. 



From the topography, excepting that of the lower zones, we obtained 

 no help in our effort to determine the former extent of the ice-sheet. 

 The ruggedness of the hills was such that from the topography alone no 

 one would infer glaciation. Oftentimes, when viewed from the ice-cap 

 or from the eastern base of the peninsula, the surface of the highlands 

 can be seen to be distinctly smoothed; but the highest parts of the land 

 invariably present a rather angular surface when viewed from the sea- 

 ward or western side. As has been said above, this applies also to minor 

 details; and deca}^ed rock, evidently preglacial in origin, was found in 

 several places. 



In the highland portions of the peninsula the weathering has been so 

 effective that the glacial strire have been removed from the bed rock ; 

 but near sealevel, where the ice staid for the longest time, and from which 

 it has only recently withdrawn, glacial striae were found in numerous 



