The London clay is lower Eocene; but in the beds of the Isle of Wight and neighbouring parts of the South of England, we have the middle and upper members of the series. They are not, however, so largely developed as in the Paris basin, where, resting on the equivalent of the London clay, we have a thick marine limestone, the Calcaire Grossier, abounding in marine remains, and in some beds composed of shells of foraminifera. The sea in which this limestone was deposited, a portion no doubt of the great Atlantic area of the period, became shallow, so that beds of sand succeeded those of limestone, and finally it was dried up into lake basins, in which gypsum, magnesian sediments, and siliceous limestone were deposited. These lakes or ponds must at some period have resembled the American "salt-licks," and were no doubt resorted to by animals from all the surrounding country in search of the saline mud and water which they afforded. Hence in some marly beds intervening between the layers of gypsum, numerous footprints occur, exactly like those already noticed in the Trias. Had there been a Nimrod in those days to watch with bow or boomerang by the muddy shore, he would have seen herds of heavy short-legged and three-hoofed monsters (Palæotherium), with large heads and long snouts, probably scantily covered with sleek hair, and closely resembling the Modern Tapirs of South America and India, laboriously wading through the mud, and grunting with indolent delight as they rolled themselves in the cool saline slime. Others more light and graceful, combining some features of the antelope with those of the Tapir (Anoplotherium) ran in herds over the drier ridges, or sometimes timidly approached the treacherous clay, tempted by the saline waters. Other creatures representing the Modern Damans or Conies--"feeble folk" which, with the aspect of hares, have the structure of Pachyderms--were also present. Creatures of these types constituted the great majority of the animals of the Parisian Eocene lakes; but there were also Carnivorous animals allied to the hyæna, the wolf, and the opossum, which prowled along the shores by night to seize unwary wanderers, or to prey on the carcases of animals mired in the sloughs. Wading birds equal in size to the ostrich also stalked through the shallows, and tortoises crawled over the mud.