as in the lower savagery generally, and had no relation to physiological factors as we recognize them.
When he comes to consider the development of the organization and culture of the aborigines he reviews the geological, biological and climatological conditions existing now and in the past since tertiary times as an essential part of the problem. He discusses the early severance of the Austral continent from Eurasia, the formation of "Wallace's line" and the subsequent geological changes, expressing the opinion that "apart from bats and insects that can fly or be carried by winds across stretches of water, mice and rats that can be carried in boats and drifting logs, Australia has received no immigrants by land from Eurasia since the Cretaceous period. She received the ancestors of her very distinctive marsupial fauna from the ancient American continent, most probably by way of Antarctica when what is now Tasmania was still a part of the continent. The lung-fish, Ceratodus, and the Monotremes, Echidna and Platypus, and such lower forms as Peripatus, are relics of a more ancient fauna once widely distributed, but her characteristic marsupials came at a later date, and the most specialized of them, the Diprodonts—kangaroos, native bears, wombats and phalangers—have been evolved within the limits of Australia itself, indicating the complete isolation of the continent for long ages, so far as influence by direct contact from outside is concerned in the case of the fauna."
After considering the various climatic changes that have taken place since Pliocene times, he comes to the conclusion that the earliest human immigrants entered Australia from the north-east in Pliocene or early Pleistocene times, and were succeeded by a later and more highly developed swarm which drove out the earlier people into what is now Tasmania, not even sparing women and children, in this following the example of the Cromagnons of Europe, who exterminated or drove out the Neanderthal people. He rejects the probability of later settlements on the coast of different parties which have introduced different beliefs and customs. He holds that these beliefs and customs have developed within Australia subsequent to the immigration of the present race and its break-up into
