It need not surprise us, therefore, to learn of reindeer and musk-sheep feeding on stunted herbage in what now constitutes Southern France. When a continuous mantle of snow and ice cloaked all Northern Europe, it is not at all surprising to find evidence of an extremely cold climate prevailing throughout its southern borders. We thus see how one piece of evidence fits into another, and therefore we may, with some confidence, endeavor to find proofs of more genial conditions when the snow and ice disappeared, and a more luxuriant vegetation possessed the land, and animals accustomed to warm and even tropical countries roamed over a large extent of European territory. In Switzerland it was long ago pointed out that after the ancient glaciers had for a long time occupied the low grounds of that country they, for some cause, retreated to the mountain valleys, and allowed streams and rivers to work over the _débris_ left behind them. At Wetzikon most interesting conclusions have been drawn. We there learn that, after the retreat of the glaciers, a lake occupied the place, which in course of time became filled with peat, and that subsequently the peat was transformed into lignite. To judge from the remains of animals and plants, the climate must have been at least as warm as that at present; and this condition of things must have prevailed over a period of some thousands of years to explain the thick deposits of peat, from which originated the lignites.27 But we also know that this period came to an end, and that once more the ice descended. This is shown by the fact that directly overlying the lignite beds are alternating layers of sand and gravel, and, resting on these, glacier-born bowlders. The same conclusion follows from the discoveries made at many other places. In Scotland it is well known that the bowlder clay contains every now and then scattered patches of peat and beds of soil either deposited in lakes or rivers. The only explanation that can be given for their presence is that they represent old land surfaces; that is, when the land was freed from ice, and vegetation had again clothed it in a mantle of green. In this cut is shown one of these beds. Both above and below are the beds of bowlder clay. The peat in the centre varies from an inch to a foot and a half in thickness, and contains many fragments of wood, sticks, roots, etc.; and of animals, numerous beetles were found, one kind of which frequents only places where deer and ruminant animals abound. Interglacial Bed.