420 _ PROF. J. LOGAN LOBLEY, F.G.S., F.R.G.S., ON 
The corresponding subject of the sub-oceanic features off 
the eastern coast of North America has been dealt with 
in considerable detail by Professor Spencer and Mr. Warren 
Upham, who have shown that these features of the sea 
bettom on the western side of the North Atlantic Ocean are 
quite analogous, if not quite similar, to those worked out by 
Professor Hull on its eastern side. 
After the papers which have appeared in the Journal of 
the Victoria Institute by Professor Hull, it is not necessary 
for me to recapitulate the facts that have been ascertained 
or the general conclusions derived from them. Sufficient 
here will be a reminder that the Continental Platform 
underlying the sea on the western coasts of Kurope has been 
found by isobathic soundings to be indented at places 
approximately opposite to present river-valleys by deep 
ravines or submarine valleys, the bottoms of which descend 
from the present littoral to the deep sea bottom outside 
the Continental Platform, cutting through what has been 
called the “Great Declivity,” by Professor Hull, and the 
“ Sub-Oceanic Slope” by Mr. Hudleston, while at the same 
time these depressions in the sea-bed widen out seawards in 
a manner similar to those of existing river-valleys. 
It has therefore been concluded that these submarine 
depressions are none other than former extensions or pro- 
longations of the river-valleys of the present land surface, 
formed by sub-aerial erosion when the continental area was 
elevated sufficiently, and this in late Geological or early 
Pleistocene times. 
Although this explanation, which has been very clearly 
and strongly advocated by Professors Hull and Spencer, may 
appear to many obvious, and the only possible explanation 
of the remarkable phenomena In question, it has been 
objected (1) that the required change of relative level of 
land and sea is too great to accord with known geological 
facts; and (2) that the submarine depressions are not 
proportionate in all cases to the size and importance of the 
rivers to the mouths of which they are respectively opposite, 
and by which they are assumed to have been formed. 
With the first of these objections I do not at present 
propose to deal, since I now wish to call attention to the 
second difficulty only, namely, the disproportion at present 
existing between some of the submarine depressions and the 
neighbouring rivers. I will therefore confine myself to the 
consideration of the question whether the elevation of land 
