It is on all hands admitted that man has existed during the whole of the present geological age. From the beds of Swiss lakes, from the shellmounds and peat-mosses of Denmark, from the caves of all Western Europe, from the gravels of ancient river-beds in the same region, the remains of successively older and older prehistoric races have been collected. The great multitude of the earliest remains of man of the present geological age are found in the river-gravels or river-drift. It is a fact well known to geologists that rivers often flow at present in beds far lower than those which they originally occupied, and that the remains of their former banks and beds may in such cases often be found at an elevation of many feet on either side of them. The most wonderful examples of these river-terraces, as they are named, in our own country (and, for that matter, in the world), are found along the Connecticut River and some of its tributaries. From three to five or more terraces may, in places, be counted, the uppermost sometimes much more than a hundred feet above the present banks. In the accompanying figure is represented the successior of terraces as they appear in France along the River Somme. The highest bank is, of course, the oldest ; but even in these highest layers of gravel, along the banks of European rivers there have been found evidences of human handiwork, in the shape of masses of flint which have been chipped to form rude but effective weapons, and flakes of flint which served as cutting implements. In England along the Thames, and in France along the Somme, such finds have been particu Chalk FIG. 26. - Terraces of the Somme. Chalk 1. Peat, twenty to thirty feet thick, resting on gravel, a. 2. Lower level gravel, with elephants' bones and flint tools, covered with loam deposited by the river, twenty to forty feet thick. 3. Upper level gravel, with overlying loam and with similar fossils, in all thirty feet thick. 4. Upland loam, without shells, five or six feet thick. larly abundant; and it was the discovery of implements at Menchecourt, near Abbeville, in the latter valley, by Boucher de Perthes, a persistent French archæologist, that first called the attention of the scientific world to what is now known as the river-drift man. One of the St. Acheul implements is represented by Fig. 27. In Fig. 28 is given a section of the gravel-pit from which these implements were taken, and it is easy to gather from the diagram that they are as old as the remains of prehistoric animals found alongside of them. Amid what surroundings the river-drift man lived in England, with the Thames flowing FIG. 27.- Flint Implement, St. Acheul. seventy feet above its present channel, and with Great Britain, not, as now, an island, but part of a great extension of the continent of Europe, let Mr. Dawkins, one of the foremost English authorities on prehistoric man, tell: "The district [valley of the Thames] was then haunted by many extinct wild animals and by living species no 1. Vegetable soil and made ground, two to three feet thick. 2. Brown loam, angular flints, and gravel, three feet thick. 3. White sand, marl, and fragments of chalk, nine feet thick. 4. Flint gravel and chalky sand, flints somewhat angular, somewhat stratified; bones of mammals; grinder of elephant at b; and flint implement at c, - ten to fourteen feet. 5. Chalk with flints. a. Part of elephant's molar tooth, eleven feet from surface. b. Entire molar tooth of a fossil elephant, seventeen feet from surface. c. Position of flint hatchet, eighteen feet from surface. longer found together in any part of the world. Stags and roe-deer lived in the forest, side by side with the |