advance in mechanical skill and execution of design, but a deeper insight into the phenomena of nature. Hence the magnitude of the differences observed between different groups of Palæolithic remains, when contrasted with the products of Neolithic culture, must largely depend on the degree of civilisation to which the owners of the former had attained. It is not an uncommon occurrence to come upon a cave containing Neolithic and Palæolithic remains separated from each other only by a thick stratum of stalagmite, as for example in Kent's Cavern, in which case there can be no doubt that the facts prove a hiatus, representing a period of time which can only be estimated by great physical changes in the environment and the extinction of some of the local fauna. But, let us suppose a case where the two culture beds are not separated by stalagmite, and that we have satisfactory evidence that the owners were contemporary with each other, how would this condition of things affect the hiatus theory? In this case the hiatus, so far as the relics are concerned, would remain precisely as before, only the element of time would be reduced to the vanishing point. The difference of technical skill disclosed by these respective remains constitutes in many instances the only barrier which has not been bridged over. Indeed, it is the occasional absence of a transition stage between the two civilisations which forms the strongest argument in support of the current opinion that the Neolithic races were immigrants into Western Europe. I am not, however, aware of any evidence which actually negatives the idea that the Quaternary men of Europe survived till the arrival of the Neolithic tribes, and that both races continued to live amicably in the same neighbourhood and ultimately amalgamated with each other. If the former were absorbed peacefully by the latter the amalgamated population would necessarily adopt the mode of living best adapted to the altered conditions of the environment, i.e., Neolithic methods. The gradual disappearance of the reindeer and other mammalia would henceforth necessitate a complete change in their manner of living. The nomadic hunter would soon sink into the herdsman, and the mechanic would readily lay aside his roughly chipped tools for those with finely ground and polished
