spread over such vast distances in a short space of time by wandering tribes.
Probably the centre from which these Palæolithic tribes swarmed off was the plateau of Central Asia, which in subsequent ages was the aboriginal home of the successive invaders both of Europe and India. We cannot refer them to any branch of the human race now alive, and they are as completely extinct among the peoples of India as among those of Europe. Their relation to the men who lived in the valley of the Thames in the mid Pleistocene age is doubtful.
The wide area occupied by this priscan population renders it very probable that it was not the same as that whose remains are chiefly met with in caverns in a limited area in Europe, and which can be identified with men now living on the earth, and whose implements are of a higher order. This question will be discussed in the following chapter, in which it will be seen that the River-drift men as well as the Cave-men used caverns for shelter in this country and in France, as is the universal custom among savages of the present day.
