REVIEWS—GEOLOGICAL EVIDENCES OF MAN’S-ANTIQUITY. 38] 
Man alone belongs. Many of these forms, not only as species, 
but as genera, are quite extinct: but none appear to have belonged 
to absolutely extinct orders. In its vegetation also, the Earth of 
the Cainozoic Age presents much that is common, in its general 
features, with the arborescent vegetation of existing Nature. A 
general similarity indeed, between that period and our own, is visible 
throughout all the sub-divisions of the organic world; but the physi- 
cal and climatical relations of the earlier time differed in many marked 
respects: from those which now prevail. Up to a comparatively late 
interval, the Cainozoic earth appears to have possessed a more or less 
uniform and warm climate, without those broad distinctions, derived 
from geographical. position, which are now experienced. This view is 
amply sustained. by fossil evidence. In the comparatively high lati- 
tude.of England. and, Northern Europe generally, not only do we find 
the shells of conularie, nautil, and similar warm-sea mollusca; but 
the Cainozoic rocks of these districts contain also palm-fruits, together 
with the remains of large ophidians and skeletons of mammals allied 
to the modern tapir, hippopotamus, giraffe, and other forms—including 
even the quadrumanous type—now limited, or nearly so, to intertropi- 
cal-habitation. « As.time passed on, however, a great climatic change 
crept slowly over all the northern lands of both the eastern and west- 
ern continents, and was apparently experienced also, in the extreme 
southern regions of the latter. Under its influence, the once warm 
climate gave gradually place to all the rigors of an Arctic winter.— 
This remarkable change was evidently accompanied, and perhaps 
im chief part produced, by enormous alterations in the previously-ex- 
isting levels of land andsea. A general elevation of northern districts, 
and a corresponding depression (with subsequent elevation) of the ad- 
jecent and more southward-lying country, must have taken place at 
one epoch of this period of cold, during which, the drift and boulder 
deposits, with their accompanying glacial phenomena, were slowly 
élaborated. All the high lands were covered by broadly-extended gla- 
ciers ; and the seas were filled with floating icebergs, bearing south- 
wards the gneissoid and other boulders of the north. This condition 
of things probably continued throughout a long interval of time.— 
During its continuance, nearly all the animal and vegetable species of 
the preceding epoch became extinct, but some few survived its changes. 
‘Between its close, and the commencement of the present state of things 
no strict line of demarcation can be drawn. The one merged slowly 
