INSTANCE OF GLACIATED RUGGED TOPOGRAPHY. 255 



hill, taken from the sea and from the land, Avill furnish as good a con- 

 trast between rugged and glaciated topography as do the two contrasted 

 views which Chamberlin published.* Not only do these glaciated hills 

 present an angular topography when viewed from a distance, but there 

 is also ruggedness of detail (see plate 27, figure 1). Some of this is due to 

 postglacial weathering and erosion, which in these high latitudes is ex- 

 tremely active, but most of it is irregularity inherited from preglacial 

 times, because the scouring action of the ice has not been sufficient to erase 

 even these minor preglacial details. There are minute ridges and valleys 

 of this nature,f and in the depressions, which are true strike valleys, 

 there are deposits of drift, proving preglacial origin for these irregulari- 

 ties. Rock basin lakes abound in these depressions, and one may pass 

 entirely around their margin upon a rock wall. These seem to be de- 

 pressions caused rather by preglacial decay than by glacial erosion. 

 Tbey are often so small and bounded by walls so angular that origin by 

 ice scouring seems absolutely impossible. Not only is there this evi- 

 dence of preglacial decay and slight erosion, but in places the rock is so 

 deepl}'' disintegrated that it is certainly the disintegration of preglacial 

 times. This decayed rock, recently uncovered, is sometimes found near 

 the ice in a place entirely too deep to have been caused in postglacial 

 times, and yet the rocks near by are rounded by ice-scouring. J The ice- 

 action has been unable to remove this decay product, but in the lower 

 areas, where ice-currents have been more active and longer at work, no 

 such decayed material was found. 



The evidence of this rugged topography and failure to remove decayed 

 rock from certain places that have been distinctly glaciated is of course 

 proof of slight ice erosion. This slight erosion may be due either to the 

 short, time of action or to the unfavorable positions presented by the 

 higher land, or to both. That it may well have resulted mainly from 

 the topographic peculiarities, and notwithstanding long continued action, 

 I am perfectly ready to believe, though not able to prove.§ A peninsula 

 rising to a height varying from 1,000 to 2,500 feet and varying in width 

 from two to four miles descends into a fiord valley whose depth below 

 sealevel is fully 600 feet in places. The valley is deep and broad, the 

 peninsula high and narrow. Even with long continued ice action it can 

 hardly be expected that the peaks of this region, rising well into the ice 



* Bull. Geol. Soc. Am., 1894, vol. vi, fig. 15, opposite p. 219. 



t Exactly this same feature was found in Baffinland, a region of similar though less differ- 

 entiated topography, which has also been subjected to general glaciation. 



1 111 one case the decayed rock still preserved glacial strise, and the ice had left it so recently 

 that lichens had not begun to cover it. 



I In this connection attention may be called to the fact that there are areas of preglacially de- 

 cayed rock in New England. 



