BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Figure 3 is another view of the same hanging valley, drawn from 
a point on the north side of Lake creek trough. Here the spur on 
the east side of the hanging valley has not a very sharp ridge, be- 
cause the next eastern valley, Galena gulch, was not strongly glaci- 
ated. There is much rock-slide material on the floor of the hanging 
valley, beneath the “spurlets” and “ravinettes” of its sharply carved 
walls. 
The trough of Lake creek glacier has in general a broadly open 
catenary curve for its cross section, as indicated in figure 4, but there 
are many subordinate departures from the perfect development of 
O 
SAY 
Fie. 3.— Crystal lake gulch hanging over the deep trough of Lake creek; look- 
ing south. 
this type form. The trough is encumbered with many rocky ledges 
and knobs, which seem to be of formidable size while one is clami 
bering over them, especially on their down-valley side where the 
plucking action of the glacier made rough work of the jointed granite; 
while the up-valley sides of the ledges are generally scoured to more 
rounded forms. This suggests that the two sides of such residual 
glaciated ledges should be called scoured and plucked, instead of 
stoss and lee; for the so-called lee side is by no means exempt, in 
such cases as are here described, from strong glacial erosion. Yet 
