pre-Neanderthals compels a revision of this complacent view of an extraordinarily difficult and complex problem. It is obvious that the needs and constructive powers of the Neanderthals, whose big clumsy hands lacked "the delicate play between the thumb and fingers characteristic of modern races", could not have been the same as those of the Crô-Magnons, and that the finely shaped implements of the Crô-Magnons could not have been evolved from the rough implements of the Neanderthals. The craftsmen of one race may, however, have imitated, or attempted to imitate, the technique of those of another.

There was a distinct break in the continuity of culture during the Palæolithic Age, caused by the arrival in Western Europe of the ancestors of Modern Man. The advent of the Crô-Magnons in Europe "represents on the cultural side", as Professor Elliot Smith says in Primitive Man, "the most momentous event in its history".