=Gravel Debris.=—­The oldest remains of the Stone Age have been found in the gravels.  A French scholar found between 1841 and 1853, in the valley of the Somme, certain sharp instruments made of flint.  They were buried to a depth of six metres in gravel under three layers of clay, gravel, and marl which had never been broken up.  In the same place they discovered bones of cattle, deer, and elephants.  For a long time people made light of this discovery.  They said that the chipping of the flints was due to chance.  At last, in 1860, several scholars came to study the remains in the valley of the Somme and recognized that the flints had certainly been cut by men.  Since then there have been found more than 5,000 similar flints in strata of the same order either in the valley of the Seine or in England, and some of them by the side of human bones.  There is no longer any doubt that men were living at the epoch when the gravel strata were in process of formation.  If the strata that cover these remains have always been deposited as slowly as they are today, these men whose bones and tools we unearth must have lived more than 200,000 years ago.

=The Cave Men.=—­Remains are also found in caverns cut in rock, often above a river.  The most noted are those on the banks of the Vezere, but they exist in many other places.  Sometimes they have been used as habitations and even as graves for men.  Skeletons, weapons, and tools are found here together.  There are axes, knives, scrapers, lance-points of flint; arrows, harpoon-points, needles of bone like those used by certain savages to this day.  The soil is strewn with the bones of animals which these men, untidy like all savages, threw into a corner after they had eaten the meat; they even split the bones to extract the marrow just as savages do now.  Among the animals are found not only the hare, the deer, the ox, the horse, the salmon, but also the rhinoceros, the cave-bear, the mammoth, the elk, the bison, the reindeer, which are all extinct or have long disappeared from France.  Some designs have been discovered engraved on the bone of a reindeer or on the tusk of a mammoth.  One of these represents a combat of reindeer; another a mammoth with woolly hide and curved tusks.  Doubtless these men were the contemporaries of the mammoth and the reindeer.  They were, like the Esquimaux of our day, a race of hunters and fishermen, knowing how to work in flint and to kindle fires.

POLISHED STONE AGE

=Lake Dwellings.=—­In 1854, Lake Zurich being very low on account of the unusual dryness of the summer, dwellers on the shore of the lake found, in the mud, wooden piles which had been much eaten away, also some rude utensils.  These were the remains of an ancient village built over the water.  Since this time more than 200 similar villages have been found in the lakes of Switzerland.  They have been called Lake Villages.  The piles on which they rest are trunks of trees, pointed and driven into the lake-bottom to a depth of several yards.  Every village required 30,000 to 40,000 of these.