Page:The Zoologist, 3rd series, vol 1 (1877).djvu/174

148 and their broken bones would bear traces of his violence. But this is not the case; whilst in England the long bones have often been found broken in such a manner as to indicate that they were split by man for the sake of the marrow which they contained.

Such are a few of the most remarkable animals which lived and died on British soil during what may be styled a period insignificant in duration as compared with the antiquity of the æons which preceded. It is not the object of the writer to deal with the details from which the various periods have been differentiated; but, in conclusion, the reader is invited to realise the belief, founded on a study of the phenomena as deciphered by such geologists as Lyell, Ramsey, Forbes, and others, that the intervals of time, both before and after the junction and separation of the British Islands and the European Continent, embrace four distinct periods. These may be set down as follows:—

Period I.—A general continental land, when the British area was a continuous portion of Western Europe.

Period II.—A submergence by which the land north of London and the Thames, and Bristol with Ireland, was reduced to an archipelago of frozen islands.

Period III.—When the sea-bed rose again, and the land equalled if not exceeded in extent that of the first period; the physical outline, as far as the mountains and rivers are concerned, being at first much the same as at present, only that the land rose higher above the sea, until the cold or glacial period, when the land first sank, and then was re-elevated, when the climate, still rigorous, gradually became milder, and the animals, many of which had