248 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



made toward the cascade, more significant testimony was furnished by 

 the ledges. Two of these, each from one to two acres in extent, occur 

 on the flat top of spurs measured at thirty-two hundred and twenty-live 

 hundred feet respectively. In both cases the outcropping rock is a de- 

 composed, light-colored gneiss cut by numerous wide bands of black 

 trap. Each spur-top is separated from the main mountain by a col ; 

 rock-slides or snow-slides would not sweep over the spurs from the 

 higher slopes, and thus disturb from their original positions any erratics 

 that may have been dropped on the spurs by a glacier. Nor would 

 general creep have removed such erratics. Wherever ledges at all 

 heights up to twelve hundred feet and above the highest shore-line of 

 postglacial submergence, were examined elsewhere in Labrador, glacial 

 boulders were very plentiful. Thus, under essentially similar climatic 

 conditions, the hills about Hebron have preserved their coating of glacial 

 drift even on slopes much steeper than on these spurs of Mt. Ford. 

 It was, therefore, a matter of no small moment to find, after prolonged 

 search, an utter failure of erratic material on both spurs. Here, too, 

 the bed-rock shows no trace of glacial smoothing. 



At sixteen hundred feet, in the notch between Mount Elizabeth and 

 Mount Ford, the Felsenmeer ceases in a steep talus-like slope. Below 

 that level the valley-floor is composed of typical, well-polished and 

 striated roches moutonnees covered with fresh subangular boulders, which, 

 from their position, being often delicately poised on the tops of nubbles 

 sloping outward on all sides, were evidently not brought thither from up 

 the valley by waste-streams or snow-creep of present day dimensions. 

 The erratic nature of these boulders of diorite and fine grained ferrugin- 

 ous schist resting on coarse hornblende gneiss, was clear in the field. 

 The ledges, though often as steep as others occurring above the sixteen 

 hundred-foot level, and though similarly devoid of vegetation, are yet 

 hardly at all riven by the frost. The stria? and grooves are well devel- 

 oped and are invariably directed down the valley. At the cascade, 

 " Korlortoaluk," they are confluent with grooves transverse to them- 

 selves and running seaward parallel to Nachvak Bay. Both sets of 

 grooves agree with corresponding sets of lunoid furrows in indicating 

 that the Nachvak trunk glacier flowed eastward and received at the 

 cascade a south-flowing tributary. (Plate 12.) 



Thus, below sixteen hundred feet on the west and south slopes of 

 Mt. Ford, there is a well glaciated zone. Above that level, steep 

 slopes of streaming Felsenmeer have deeply covered the ledges. At 

 twenty-one hundred feet and above, the ledges are in the utmost con- 



