Everything the glacier couldn’t break, it pushed along in front of it or plowed beneath it. Rocks were ground to gravel, and soil was caught into the ice, which afterwards melted and ran off as muddy water. Hard tools of flint sometimes remained whole. Human bones weren’t so hard; it’s a wonder _any_ of them lasted. Gushing streams of melt water flushed out the debris from underneath the glacier, and water flowed off the surface and through great crevasses. The hard materials these waters carried were even more rolled and ground up. Finally, such materials were dropped by the rushing waters as gravels, miles from the front of the glacier. At last the glacier reached its greatest extent; then it melted backward toward the north. Debris held in the ice was dropped where the ice melted, or was flushed off by more melt water. When the glacier, leaving the land, had withdrawn to the sea, great hunks of ice were broken off as icebergs. These icebergs probably dropped the materials held in their ice wherever they floated and melted. There must be many tools and fragmentary bones of prehistoric men on the bottom of the Atlantic Ocean and the North Sea. Remember, too, that these glaciers came and went at least three or four times during the Ice Age. Then you will realize why the earlier things we find are all mixed up. Stone tools from one camp site got mixed up with stone tools from many other camp sites--tools which may have been made tens of thousands or more years apart. The glaciers mixed them all up, and so we cannot say which particular sets of tools belonged together in the first place. “EOLITHS” But what sort of tools do we find earliest? For almost a century, people have been picking up odd bits of flint and other stone in the oldest Ice Age gravels in England and France. It is now thought these odd bits of stone weren’t actually worked by prehistoric men. The stones were given a name, _eoliths_, or “dawn stones.” You can see them in many museums; but you can be pretty sure that very few of them were actually fashioned by men. It is impossible to pick out “eoliths” that seem to be made in any one _tradition_. By “tradition” I mean a set of habits for making one kind of tool for some particular job. No two “eoliths” look very much alike: tools made as part of some one tradition all look much alike. Now it’s easy to suppose that the very earliest prehistoric men picked up and used almost any sort of stone. This wouldn’t be surprising; you and I do it when we go camping. In other words, some of these “eoliths” may actually have been used by prehistoric men. They must have used anything that might be handy when they needed it. We could have figured that out without the “eoliths.” THE ROAD TO STANDARDIZATION