458 A POPULAR EXPOSITION OF THE 
appear to be of the same age and character as those which at Amiens, 
Abbeville, Creil, Suffolk, Bedford, and elsewhere, contain flint imple- 
ments of rude manufacture, mixed with the remains of the mam- 
moth and other types, both living and extinct. The arrow-heads and 
other stone implements so constantly found in our Canadian super- 
ficial deposits, are of a much less primitive character, however, and 
belong in all probability to a comparatively recent date. 
Conditions under which the Drift amd Post-glacial deposits were 
accumulated.—It is now universally admitted that the various deposits 
of the Drift, and immediately succeeding period, were accumulated 
under conditions more or less resembling those which at present pre- 
vail in Arctic latitudes. This conclusion is based chiefly on the 
following facts: —(1). The resemblance of the polished, rounded, and 
striated surface of the rocks beneath the Drift, to the surface-rocks 
of Alpine regions in which glaciers prevail, or to those which in 
higher latitudes have been subjected to glacial action generally. 
(2.) The greater development and extension of glaciers in these 
regions, during the interval between the close of the Cainozoic period 
and the commencement of the existing epoch, properly so-called. 
(3.) The evident signs of the occurrence of ancient glaciers in lower 
and more southern districts during the same period. (4.) The appa- 
rent impossibility of any other agency than that of ice to have effected 
the transportation of the numerous boulders scattered throughout 
Drift-covered regions: many of these boulders, including some of 
large size, having been carried across lakes, seas, ravines, and other 
obstacles, to far distant localities. And (5), the general arctic or 
northern character of the mollusca, &c., found in the modified drift 
or Post-glacial deposits of various countries. 
The fossils which occur in Cainozoic strata, prove clearly the preva- 
lence of a warm, if not of a tropical climate, throughout the period 
during which these strata were deposited. ‘Towards the close of the- 
Cainozoic Age, however, the relative levels of land and water, through- 
out all the more northern and extreme southern portions of the globe, 
appear to have undergone great though gradual changes, during which, 
a period of increasing cold came slowly on, covering all the more ele- 
vated districts with enormous glaciers, filling the sea with floating 
icebergs, and compelling a general southerly migration of such life- 
forms as were able, by this or other means, to resist its destructive 
influence. The greater part of Canada must certainly have been 
