So, you see, the remains of these early men cover a pretty wide area. In thinking of the life of those early days we must remember that the aspect of Britain was very different then from what it is now, for in that far-back time these islands were a part of the Continent of Europe, and the North Sea and English Channel were just valleys, with rivers flowing through them, tributaries of the Rhine. There were no insurmountable obstacles to cross between the Continent and these regions, and animals and early man gradually roamed into this part of the world. Geology teaches us a good deal concerning the changes the surface of the ground has undergone. The land was very much higher than it is now--Snowdon, for instance, was at least six hundred feet higher then--and the climate was very much colder. That race of men, apparently, has quite died out. In the course of ages rivers and seas have flowed over the places where these stone tools had been dropped, and, year after year throughout the ages, the drift brought down by the rivers covered them inch by inch and foot by foot. Great changes have taken place in the surface of the land, some suddenly, but most of them very, very slowly. The land has risen, and sunk again, and long, long ages of sunshine and storm, of ice and snow, of stormy wind and tempest, have altered the surface of the country. Those very ancient men, who lived in the Early Stone Age, are called Cave-dwellers, because they lived apparently in caves, and River-drift Men and Lake-dwellers, because the roughly chipped tools are found in the _drift_ of various rivers and lakes. The Cave-man's weapons and tools were made of chipped flint, which he found broken on the surface of the ground, and these he chipped into shape. They are usually more or less oval, sometimes roughly in the form of a spear-head. Others are borers, or awls, for piercing holes in skins. For rougher work he had hammer-stones, with flat edges, and sharp bits of stone for scrapers. Amongst many other places where these relics have been found in considerable numbers is the Thames valley. They are met with in the higher gravels, on levels now many feet higher than they were in the Cave-man's day, for the surface has risen considerably; and we conclude that there must have been a good many of these people in that neighbourhood. [Illustration: _Chipped Flint Weapons_] CHAPTER III The Pit-dwellers