Glacierfi on<l fHacial Radiants — Claypole. 855 
the Rocky mountains, from which iu like manner the ice radi- 
ated west into the Pacific ocean and north and east in the lower 
lands there lying. 
This view of the ice-age enables us to understand another 
fact. The Canadian surveyors have several times remarked 
that the distribution of the drift in the ojreat inland basin of the 
Mackenzie river indicates rather the action of floating ice than 
the determinate action of a laud-glacier. Obviously the theory 
here advocated will allow us to suppose that during at least 
some part of the time of duration of the ice-age a gulf of the 
Arctic ocean may have reached up to a considerable distance 
southward over this basin and have afforded a means for carry- 
ing ice-bergs and drift inaterial. In that case we should expect 
however to find some traces of the presence of the sea in that 
region. Whether or not this is the case must be left to be de- 
termined by the future labors of the Canadian surveyors in this 
difficult and little explored country. 
There is yet one oilier point that deserves a moment's con- 
sideration in passing. T allude to the depression which occurred 
in the northern part of the continent probably during the glacial 
era. Without entering here on any discussion of the causes of 
this depression about which great divergence of opinion exists 
the geological evidence clearly substantiates the statement that 
about that epoch some of the northern parts of the continent did 
subside to a very considerable extent — many hundred feet at 
least, — from which depression they have never fully recovered. 
Hence these lands now lie lower than they lay in pre-glacial 
days. The intricate lines of many of our northern coasts, such 
for instance as those of Maine, S. Greenland, British Columbia 
and Alaska, cannot as formerly be attributed to the eroding 
action of ice, but must be explained on the theory that they 
are submerged Hues of inlaud drainage— the beds of streams 
that were once above the sea but are now depressed below it 
and into which the sea consequently runs as far as the level 
will allow. A very cursory examination of the valley of any 
river having many tributaries will show how closely in accord- 
ance with nature is the above explanation. The intricacy and 
the depth of these fiords show little resemblance to ice- valleys, 
even if the eroding power of ice were sufficient for the purpose^ 
