FOSSIL REMAINS. 
611 
mammoths were destroyed ; and the enormous accumulation of the wreck of moun- 
tains that has been mixed up with their remains points to some great aqueous 
revolution as the cause by which their sudden and total extirpation was effected. 
It cannot be contended, that like small and feeble species, they may have been 
destroyed by wild animals more powerful than themselves. The bulk and strength 
of the mammoth and rhinoceros, the two largest quadrupeds in the creation, render 
such an hypothesis utterly untenable. 
The state of the argument then respecting the former climate of the polar regions 
is nearly as follows : — It is probable that in remote periods, when the earliest strata 
were deposited, the temperature of a great part of the northern hemisphere equalled 
or exceeded that of our modern tropics, and that it has been reduced to its present 
state by a series of successive changes. The evidence of this high temperature and of 
these changes consists in the regular and successive variations in the character of 
extinct plants and animals which we find buried one above another in the successive 
strata that compose the crust of the globe. These have in modern times been investi- 
gated with sufficient care and knowledge of the subject to render it almost certain 
that successive changes, from extreme to moderate heat, have taken place in those 
parts of the northern hemisphere which constitute central and southern Europe ; 
and although we are not yet enough acquainted with the details of the geology of 
the arctic regions to apply this argument to them with the same precision and to 
the same extent as to lower latitudes, still we have detached examples of organic 
remains in high latitudes sufficient to show the former existence of heat in the re- 
gions where they are found — a few detached spots within the arctic circle that can 
be shown to have been once the site of extensive coral reefs are as decisive in 
proof that the climate in these spots was warm at the time when these corals lived 
and grew into a reef, as, on the other hand, the carcass of a single elephant pre- 
served in ice is decisive of the existence of continual and intense cold ever since 
the period at which it perished. We have for some time known that in and near Mel- 
ville Island, and it has been ascertained by Captain Beechey’s expedition, that at Cape 
Thompson, near Beering’s Strait, there occur within the arctic circle extensive rocks 
of lime-stone containing many of the same fossil shells and fossil corals that abound 
in the carboniferous lime-stone of Derbyshire: the remains of fossil marine turtles 
also (chelonia radiata) have been ascertained by Professor Fischer to exist in Si- 
beria. These are enough to show that the climate could not have been cold at the 
time and place when they were deposited j and the analogy of adjacent European 
latitudes renders it probable that the same cooling processes that were going on m 
them extended their influence to the polar regions also, producing successive 
reductions of temperature, accompanied by corresponding changes in the animal 
