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Glaciation of Eastern Canada. 331 
Dame Range, in Quebec, and its continuation south-west- 
wardly along the International boundary, likewise shed the 
ice in both directions at about right angles to the main axis 
of the chain, that is, nearly south-eastward and north- 
westward ; while the Archean Area north of the St. 
Lawrence and great lakes sent sheets of ice down 
its slopes in all directions around its circumference. On 
the east side of Hudson Bay, the ice moved directly west- 
ward into its basin according to Dr. R. Bell and Mr. 
A. P. Low. 
Considerable areas of rock surface in the interior and 
more elevated portions of Hastern Canada, where gather- 
ing grounds for glaciers may be supposed to have existed, 
are without strie or other evidence of glaciation, the 
decomposed rock lying undisturbed, except from sub- 
erial action, and boulder-clay being absent. Occa- 
sional smaller patches of similar character are met with 
near the coast. These during the ice age were probably 
covered by snow only, or by ice which had little or no 
motion. 
The extent and thickness of the glaciers cannot as yet 
be satisfactorily determined from the data at hand. But it 
is evident some of them were quite large, and the larger 
ones appear to have been on the southern slopes of the Ap- 
palachians and Laurentides. The cause of this is not ap- 
parent, but as regards those of the former mountain range, 
it may be due, insome measure, to the difference in the 
steepness of the slopes on either side of it. The south-east- 
ern slope is long, much broken, and has numerous compara- 
tively level areas upon it. As the rate of motion would be 
slower on this slope, the ice would necessarily accumulate 
in Jarger sheets in the depressions and on level tracts. 
On the shorter and more abrupt slope of the St. Lawrence 
the motion of the glaciers would be more rapid, they 
would more readily debouch in the estuary or sea, and 
hence there would be less chance for accumulation in large 
sheets, 
The evidences of the action of icebergs or floating ice 
