< 'orrespondena . 201 
article, by the way, was not a summary of my report, but only of a 
single topic), your reviewer, after referring to the hypothesis that the 
subglacial streams bore their debris onward to their debouchures in the 
open sea, says : "If this were the case, however, we should expect large 
submarine deposits of gravel and sand, like the materials of the osars, 
to have been amassed at those places. The absence of such deposits 
seems to render this view very doubtful, etc." 
The mooted questions of interpretation, so far as Maine is concerned, 
between the rival sub- and super-glacial hypotheses have been treated 
in detail in my report, and need not further be referred to here. But 
the words which I have italicized seem to assume that such deposits as 
are above described are absent. This involves an important question of 
fact which appears to demand immediate attention, partly to prevent 
misapprehension and partly to obtain new facts if possible. 
1. The consequences of the hypothesis under review were correctly 
stated by you — there ought to be accumulations of glacial sediments 
in the sea near the mouths of the glacial rivers. Since the southern 
ends of the osars are near the present shore line, the accumulations 
which were amassing at the time the most southern of the coastal 
gravels were being deposited, would now be, on my hypothesis, beneath 
the ocean. The question now arises whether there are such bodies of 
glacial sediments on the sea bottom. In order to solve the problem, I 
examined the most detailed of the charts of the Coast and Geodetic 
Survey, but found grave practical difficulties. The soundings were not 
made by geologists nor for a geological purpose. They are often one- 
fourth to one-half mile apart. These are sufficient for the purposes of 
navigation but do not afford data for mapping submerged osars. The 
charts cover only a few miles of the ocean, probably only a third of the 
breadth of that portion of the present sea area which was covered by 
ice at the time of maximum glaciation. The soundings often show 
hills on the floor of the ocean, but we do not know what they are com- 
posed of. Here and there the bottom is stated to be muddy, sandy, 
gravelly, etc., but at too great distances to be of much help. Do any 
of your readers know whether the Coast Survey observers distinguished 
between unmodified till and water-rolled gravel ? Occasionally there 
are reaches of sand and gravel that are suggestive of glacial marine 
deltas. We have to consider the probability that much of the coarse 
gravel would by this time have become covered by clay. On the whole 
the data were too few to be regarded as conclusive. 
While, then, I have not been able to find positive affirmative proof 
that bodies of glacial sediments exist beneath the ocean, yet, on the 
other hand, I know of nothing that proves they are not there. For 
years I have been trying to gather from captains of fishing vessels and 
others facts regarding this question. It will be a great favor if you or 
any of your readers will publish observations bearing on the subject. 
2. As for that portion of the ice-covered area that was submerged in 
late glacial time but has since been elevated above the sea, there is no 
absence of such accumulations of glacial sediments as are above de 
