24b bulletin: museum of comparative zoology. 



interior, whose craggy peaks have evidently never "been ground down 

 by land-ice into domes and rounded tops." Bell, in 1884, published his 

 observations on the Torngats. He stated: "The mountains around 

 Nachvak are steep, rough-sided, peaked, and serrated, and have no ap- 

 pearance of having been glaciated, excepting close to the sea-level. The 

 rocks are softened, eroded, and deeply decayed. . . . Throughout the 

 drift period, the top of the coast range of the Labrador stood above 

 the ice and was not glaciated, especially the high northern part." 1 



But this serrate topography is not of itself sufficient to disprove that 

 the glaciatiou was general in the Torngats ; it implies with certainty 

 only that the glaciation of the range was weak at higher levels at the 

 time when the hummocky plateau of southern Labrador was remodelled 

 by the ice. Tarr has shown that, notwithstanding the augularity of its 

 summits, Mt. Ktaadn in Maine was completely covered by ice in the last 

 glacial epoch. The present form is understood in the light of the facts 

 that Tarr has emphasized : (1) The rapidity of frost attack is so great at 

 high altitudes that the shape of a glaciated knob may be significantly 

 changed even in postglacial time. (2) The summits have been longer 

 exposed to the weather than the valleys, since the latter would be occu- 

 pied by local glaciers during late glacial time. (3) Although the sum- 

 mit was ice-covered, it would presumably be above the zone of maximum 

 glaciation. (4) The lack of timber in the higher parts of the mountain 

 would give the weather permission to produce serrate topography which 

 would not be expected in the lower vegetated belt. 2 In summarizing 

 the results of his studies of the Cornell glacier, Tarr notes further stric- 

 tures on the same criterion of non-glaciation. 3 He states in effect that 

 we should expect less erosion by ice in the higher parts, because of the 

 slower motion of the ice in the upstream portion, and because of the 

 clean character of the ice above the debris zone. The valleys should 

 necessarily show more intense erosion than the mountain-tops, since 

 thick glacier ice would appear first in the valleys as the ice-cap waxes, 

 and still exists there after the waning ice-cap had deserted the summits. 

 He has, moreover, found erratics on Mt. Schurmann, a ragged nunatak 

 in the Cornell glacier. Lastly, he notes that serrateness may be only 

 apparent, the impression of raggedness being due to the common posi- 

 tion of the observer on the lee or down-stream side of a glaciated head- 

 land, as he approaches such a coast as that of West Greenland. "While 



1 Rep. Geol. Sur. Canada, 1884, Part DD, pp. 14 and 37 ; cf. Report for 1885, 

 Part DD, p. 7, and Scottish Geog. Mag., Vol. 11, 1895, p. 340. 



2 R. S. Tarr, Bull. Geol. Soc. Amer., 1900, Vol. 11, p. 437. 

 a Bull. Geol. Soc. Amer., 1897, Vol. 8, p. 252. 





