DALY: GEOLOGY OF THE NORTHEAST COAST OF LABRADOR. 261 
dropped again just at the limit where, on account of the depth, the surf 
is no longer effective in moving boulders resting on the bottom, the 
erratics would further build up the wall constructed by the undertow. 
Very close to that limit of effective wave-wash, the winter-ice, because 
of the depth at which the boulders lie (submerged at high tide), would 
not be able to buoy up the heavy masses and float them away. 
If the land had, in postglacial time, ever been higher than to-day, 
erratics won from the wave-swept zone would have moved seaward 
beyond their present position through the operation of the causes just 
described. During a subsequent uplift of the land, the boulders could 
not, in any large number, be recalled to the new shore-line. The actual 
magnitude of the average barricade is certainly too great to warrant the 
belief that the waves would, under this condition, undo what they had, 
during the progress of elevation, accomplished. The character of the 
material making up the barricade and its organic relation to the wave- 
swept zone forbid, thus, the assumption of a secondary uplift following 
a former greater postglacial depression of the land than we now see. 
One is forced to reject the idea that the barricades have been princi- 
pally formed by ’longshore transport of boulders. The walls are devel- 
oped very uniformly at the mouth and head, and along the sides of long 
bays. If they were the result of ’longshore deposition by floating ice, 
we should expect the accumulation of dropped boulders to be quite 
uneven, most pronounced where floes and pans most frequently strand, 
and, at other points, scarcely begun. It cannot be denied that coast-ice 
does carry boulders in this way, but one may justly question its ability 
to have performed so great an amount of work as that demanded in the 
construction of the barricades. For this hypothesis implies that the sea- 
floor along the broad track of the annual field-ice is peppered over with 
glacial erratics far greater in number than could have been furnished by 
the wave-swept zone, if that zone had had anything like the average 
proportion of the drift now seen above the highest shore-line. 
ConTINUANCE OF ELEvation. — We cannot doubt that the elevatory 
process continues in both Labrador and Newfoundland. The almost 
universal belief of the old settlers on these shores is that in no other 
way can the changes in depth at familiar localities be explained. With 
no theory to support or refute, many reputable observers among the 
fishing population state that they have time and again noted, during 
periods of from thirty to sixty years, cases where rock-ledges have come 
perceptibly nearer the sea-surface, where new channels have had to be 
sought among the shoals for the passage of their fishing-boats, and where 
