Page:Early Man in Britain and His Place in the Tertiary Period.djvu/219

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We can readily picture to ourselves, by the aid of these two narratives, the vast migratory bodies of bison and reindeer, a sea of tossing manes and horns, or a moving forest of antlers, passing upwards by the great gaping chasm, overhung by the Peak Castle, to the heights dividing the tributaries of the river Trent from those of the Dee and the Mersey, followed by the wild beasts as in North America and Northern Asia. The bison and reindeer, however, now are not known to inhabit the same country at the same time, and therefore we cannot suppose that this was the case in Britain in the Pleistocene age. The difficulty may be explained by the supposition that they occupied the district at different seasons, which, as we have already seen, were more sharply contrasted than they are at the present time. An examination of their bones and teeth proves that the bisons were here with calves not more than three or four months old, that is to say, within three or four months of calving time in May, in other words, in the summer and the autumn. The remains of the young reindeer, on the other hand, are very scarce, and only one milk-molar, the last in the series, possesses imperfect fangs; from which it may be concluded that they were not in the district in the summer and autumn—their calving time, according to Sir John Eichardson, also being May. They were, therefore, here in the winter time, and perhaps in the early spring. This undesigned piece of evidence is a strong confirmation of the truth of the views held by Sir Charles Lyell and myself that the association of animals, not now found together in Pleistocene deposits, is due to seasonal migrations.