was tropical or sub-tropical—that is to say, in middle Pleistocene or late Pleiocene times. If man really existed in England in Pleiocene times, in favour of which view there appears to be strong evidence, he would have been in all probability the companion of the extinct tropical mammalia found deposited in the Cromer Forest beds, and some of which belonged to Meiocene times. This forest was in existence at the close of the Pleiocene era, and stretched from Cromer far away into what is now the German Ocean, uniting Norfolk and Suffolk to Holland and Belgium; but soon after the commencement of the Pleistocene period the North Sea gradually swept over the old continent between Britain on the west and Sweden, Denmark, and the Netherlands on the east, thus converting the old forest at Cromer into the bed of the ocean, where the stumps of the trees may now be seen embedded in deposit at very low tide. Immediately after the disappearance of this forest the first period of glaciation commenced, from which moment until the close of the glacial periods the alternations in temperature and surface level were frequent and of enormous magnitude, the correct sequence of which changes we have as yet no proper conception. If we go back to the commencement of the Tertiary great division of the geological periods, we shall find that, at the beginning of the Eocene deposits, the Secondary cretaceous rocks had been upheaved from the bottom of the sea, and had become the dry ground of a large continent, of which the British Islands formed a part; so that Eocene fauna and flora in England had free communication with continental life. The relative positions of land and water during this first Tertiary period were as follows: The great continent spread from North America to Europe, uniting Canada, Greenland, Iceland, Faroes, Shetlands, Orkneys, Ireland, and Britain (except south-east portion), with Scandinavia and Spitzbergen on the north-east, and with France (Brittany) and Spain on the south. There were three seas—the North Sea, which, like a wedge with its point downwards, separated Greenland, Iceland, and Faroes from Spitzbergen and Scandinavia; the South-Eastern Sea, which stretched from the top of Denmark to Boston in Lincolnshire, thence to Lyme Regis in Dorsetshire, and on to Cherbourg, covering the whole of the east and south-east of England; and the Atlantic, which was separated from the North Sea by Iceland, Faroes, and intermediate lands, and from the South-Eastern Sea by the British Islands, Western France, and intermediate lands. These Eocene seas teemed with fish now only found in more Southern latitudes; while the inland lakes and rivers abounded with reptilian life. On the land tropical flora and fauna flourished, among the former being palms, cypresses, and giant cacti, and among the latter, in Lower Eocene times, large numbers of marsupial species, in the Middle Eocene also lion-like carnivora, and