The attempt to place this long chapter of prehistory on a historical basis has many dangers, of which I am fully aware. After weighing the evidence presented by the eminent authorities in these various branches of science, I have presented my conclusions in very definite and positive form rather than in vague or general terms, believing that a positive statement has at least the merit of being positively supported or rebutted by fresh evidence. For example, I have placed the famous Piltdown man, _Eoanthropus_, in a comparatively recent stage of geologic time, an entirely opposite conclusion to that reached by Doctor A. Smith Woodward, who has taken a leading part in the discovery of this famous race and has concurred with other British geologists in placing it in early Pleistocene times. The difference between early and late Pleistocene times is not a matter of thousands but of hundreds of thousands of years; if so advanced a stage as the Piltdown man should definitely occur in the early Pleistocene, we may well expect to discover man in the Pliocene; on the contrary, in my opinion even in late Pliocene times man had only reached a stage similar to the _Pithecanthropus_, or prehuman Trinil race of Java; in other words, according to my view, man as such chiefly evolved during the half million years of the Pleistocene Epoch and not during the Pliocene. This question is closely related to that of the antiquity of the oldest implements shaped by the human hand. Here again I have adopted an opinion opposed by some of the highest authorities, but supported by others, namely, that the earliest of these undoubted handiworks occur relatively late in the Pleistocene, namely, about 125,000 years ago. Since the Piltdown man was found in association with such implements, it is at once seen that the two questions hang together.