About 10,000 B.C. the geography of the world was very similar in its general outline to that of the world to-day. It is probable that by that time the great barrier across the Straits of Gibraltar that had hitherto banked back the ocean waters from the Mediterranean valley had been eaten through, and that the Mediterranean was a sea following much the same coastlines as it does now. The Caspian Sea was probably still far more extensive than it is at present, and it may have been continuous with the Black Sea to the north of the Caucasus Mountains. About this great Central Asian sea lands that are now steppes and deserts were fertile and habitable. Generally it was a moister and more fertile world. European Russia was much more a land of swamp and lake than it is now, and there may still have been a land connexion between Asia and America at Behring Straits. It would have been already possible at that time to have distinguished the main racial divisions of mankind as we know them to-day. Across the warm temperate regions of this rather warmer and better-wooded world, and along the coasts, stretched the brownish peoples of the Heliolithic culture, the ancestors of the bulk of the living inhabitants of the Mediterranean world, of the Berbers, the Egyptians and of much of the population of South and Eastern Asia. This great race had of course a number of varieties. The Iberian or Mediterranean or “dark-white” race of the Atlantic and Mediterranean coast, the “Hamitic” peoples which include the Berbers and Egyptians, the Dravidians; the darker people of India, a multitude of East Indian people, many Polynesian races and the Maoris are all divisions of various value of this great main mass of humanity. Its western varieties are whiter than its eastern. In the forests of central and northern Europe a more blonde variety of men with blue eyes was becoming distinguishable, branching off from the main mass of brownish people, a variety which many people now speak of as the Nordic race. In the more open regions of northeastern Asia was another differentiation of this brownish humanity in the direction of a type with more oblique eyes, high cheek-bones, a yellowish skin, and very straight black hair, the Mongolian peoples. In South Africa, Australia, in many tropical islands in the south of Asia were remains of the early negroid peoples. The central parts of Africa were already a region of racial intermixture. Nearly all the coloured races of Africa to-day seem to be blends of the brownish peoples of the north with a negroid substratum. A Diagrammatic Summary of Current Ideas of the Relationship of Human Races