254 R. S. TARR — FORMER EXTENSION OF CORNELL GLACIER. 



as in land elevation. Moreover, there would be a variation according to 

 the point of view. Seen from a vessel at sea, the peak will naturally be 

 more angular than when viewed from the land side, which is the direc- 

 tion from which the ice moved, and hence in which the ice erosion was 

 greatest. This difference in ruggedness would decrease as the time of 

 ice action increased ; therefore marked ruggedness may possibly be con- 

 sidered as an evidence that the ice covered the high land only for a brief 

 period through this seems by no means certain, since there is little op- 

 portunity for ice erosion on the high points. 



INSTANCE OF GLACIATED RUGGED TOPOGRAPHY. 



On the Upper Nugsuak peninsula (see plate 25), where the Cornell 

 party spent a month, there was a chance to test the validity of this in- 

 terpretation. The Devil's Thumb * rises about 2,650 feet above the sea- 

 level and presents a seaward face of rugged outline (plate 26). Trans- 

 ported pebbles were found on its top. At the end of the Upper Nugsuak 

 peninsula Wilcox Head rises 1,400 feet above the sea as a rugged and 

 serrated peak, and upon it are patches of boulder-clay and innumerable 

 transported blocks. Numerous other points on the peninsula reach to 

 elevations between 1,000 and 2,600 feet. These higher peaks are very 

 angular, but upon the tops of all of them that were ascended numerous 

 transported fragments were found. On the crest of the nunatak named 

 mount Schurman, about seven miles from the margin of the ice-sheet, 

 transported pebbles were obtained at an elevation of 2,210 feet above the 

 sea and 1,000/eet above the ice-surface at the western base of the moun- 

 tain. This peak has been very recently uncovered, and is extremely 

 rugged both in general form and in details. The rise of 1,000 feet on the 

 western face is a precipice from top to bottom. If one fell from the edge 

 he would pass entirely to the bottom. At the same time the lower areas 

 of land in the vicinity of this peninsula are well rounded and smooth, 

 as has been noted in other parts of the Greenland coast. 



From this it may fairly be concluded that not only may we expect 

 greater irregularity of form in the higher peaks than in the lower lands 

 of a region that has been glaciated, but also that we have here in the 

 Upper Nugsuak peninsula an excellent illustration of this. Views taken 

 in various parts of this peninsula excel in ruggedness the peak which 

 Professor Chamberlin picturesf as proof of nonglaciation, and yet upon its 

 angular surface transported pebbles were found ; also views of the same 



* This is the Devil's Thumb as given on the Danish and British Admiralty charts. The real 

 Devil's Thumb of the Arctic explorers is some 40 or 50 miles to the north of this. 

 fBull, Geol- Soc. Am., vol. vi, 1894, p. 219 ; see also Salisbury : Jour. Geology, vol, iv, 1896, p. 773. 



