110 DISTRIBUTION OF EXTINCT ANIMALS. [PART I. 
Historic Period—lIn tracing back the history of the organic 
world we find, even within the limits of the historical period, 
that some animals have become extinct, while the distribution of 
others has been materially changed. The Rytina of the North 
Pacific, the dodo of Mauritius, and the great auk of the North 
Atlantic coasts, have been exterminated almost in our own 
times. The kitchen-middens of Denmark contain remains of 
the capercailzie, the Bos primigenius, and the beaver. The first 
still abounds farther north, the second is extinct, and the third 
is becoming soin Europe. The great Irish elk, a huge-antlered 
deer, probably existed almost down to historic times. 
Pleistocene or Post-Pliocene Period.—We first meet with proofs 
of important changes in the character of the European fauna, in 
studying the remains found in the caverns of England and France, 
which have recently been so well explored. These cave-remains 
are probably all subsequent to the Glacial epoch, and they all 
come within the period of man’s occupation of the country. Yet 
we find clear proofs of two distinct kinds of change in the 
forms of animal life. First we have a change clearly trace- 
able to a difference of climate. We find such arctic forms as 
the rein-deer, the musk-sheep, the glutton, and the lemming, 
with the mammoth and the woolly rhinoceros of the Siberian 
ice-cliffs, inhabiting this country and even the south of France. 
This is held to be good proof that a sub-arctic climate pre- 
vailed over all Central Europe ; and this climate, together with 
the continental condition of Britain, will sufficiently explain 
such a southward range of what are now arctic forms. 
But together with this change we have another that seems at 
first sight to be in an exactly opposite direction. We meet 
with numerous animals which now only inhabit Africa, or South 
Europe, or the warmer parts of Asia. Such are, large felines— 
some closely related to the lion (Felis spelwa), others of alto- 
gether extinct type (Machairodus) and forming the extreme de- 
velopment of the feline race ;—hyznas ; horses of two or more 
species ; and a hippopotamus. If we go a little further back, to 
the remains furnished by the gravels and brick-earths, we still 
find the same association of forms. The reindeer, the glutton, 
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