1872.] 67 (Perry. 
accomplishment of such work, unless they gradually increased in size 
and thus.sank deeper in the sea as they gradually advanced south- 
ward —a supposition which contradicts all we know of such bodies 
of ice. Indeed, to cite a single instance, unless the supposed subsi- 
dence at St. Johns, in Canada, were vastly greater than it was a few 
miles further south, icebergs could not have entered the Champlain 
Basin from the north so as to do the work, which ice or some kindred 
instrumentality has wrought at so low a level as the surface of the 
lake, to say nothing of the erosion of subjacent rocks. So river 
channels, particularly those extending easterly or westerly, could not 
have been formed by floating ice from the Arctic region under the 
conditions named. And of course the supposed depression and 
presence of icebergs is in no wise able to account for the existence of 
pot-holes on the summits or flanks of isolated hills and mountain 
peaks. 
And the iceberg hypothesis seems to be no more tenable, when 
we examine the overlying deposit of drift. Of course the melting 
of such masses of ice must have been accompanied by the laying 
down of a considerable amount of detrital matter. This is evident 
toall. So, too, it is clear that this material would have been very 
heterogeneous in its composition. Indeed, had it come from an Arc- 
tic continent, the question at once arises, whether it must not have 
been, in a far greater degree, different from the consolidated rocks 
of New England, than is the case with the existing drift. We also see 
that bergs of northern ice would not have been able, if the supposition 
be true, to deposit the largest proportion of this detrital matter within 
a few miles of its origin— matter which was clearly ground from 
ledges lying only at a short distance to the north, or the north-west, 
of its present position. And it is by no means evident that this ma- 
terial would have been laid down ina jumble, as was clearly the 
case with typical drift. It should be ever remembered that the 
wasting of the icebergs must have been gradual — not sudden, as it 
were at a stroke, as seems to be implied in many of the current ex- 
planations. Accordingly, as the bergs slowly thawed, the particles 
of matter, and especially the vast amount of finely comminuted ma- 
terial, whether the masses of ice were stranded or in motion, could 
not have been readily left in a confused heap, wholiy unstratified 
and without regularity of form. They must have been laid down, 
so far as one can now judge, with considerable uniformity and order, 
as they successively fell, particle by paritcle, into the sea, and were 
