In neither the first nor second stone period had men yet learned to build any kind of habitations. They lived in caves simply, like wild animals. On the banks of the river Vezère in France, which has cut its way deeply through the rock, there are some celebrated caves once inhabited by pre-historic men, and some of them are very large. They were most likely hollowed out in the cliff by water, and many generations of men lived here. In one of them four human skeletons were found, with plenty of stone and flint tools, besides the bones of the mammoth and lion, reindeer and other animals. The mammoth then as well as the reindeer lived at that time in the valley of the Vezère. There is no doubt that these caves were inhabited at separate times by people who used only the roughest and simplest stone tools, and by others who had made some progress and could polish their tools and make them of bone and could scratch pictures of animals upon slips of bone and slate. It is curious that all these drawings are side-view drawings, and they are only outlines, just like the drawings of children now, and the Esquimaux of the Arctic regions; because these people, although they were grown up, had not discovered the art of drawing in perspective and shading the figures. Still the pictures are wonderfully true to nature, and must have been copied from living animals. There is no earthenware in any of these caves, so that the useful art of making pottery had not been discovered, neither is there any in the caves in Switzerland, where the bones of the mammoth, lion, and rhinoceros are also found, and the tools and weapons are much the same as those in the French caverns. It is impossible to say whether the cave-dwellers of France and Switzerland lived at the same time exactly, but they were in about the same condition of civilization, and they must both have been quite familiar with the appearance of the mammoth and lion, and other animals, which are not mentioned in any history, however old it may be, as inhabitants of these countries. A discovery has lately been made in France of a large cavern near Belfort, in the limestone rock, which has been covered up for ages. The quarrymen while cutting out the stone came upon a small opening leading into a very large cave, in which there was a great quantity of human skeletons and bones and some beautifully ornamented vases, polished stone bracelets, and a mat of plaited rushes. To these people, then, the arts of pottery and weaving were known, and this was probably one of their burying-places. They were evidently much more civilized than the ancient people of the valley of the Vezère; but this cave must also be of a great age, and its inhabitants have left no record of their history in any kind of writing.