Note 1 — Chapter I · PREHISTORIC RACE MOVEMENTS IN AFRICA

A hundred thousand years ago the Red Sea may have been a long, isolated lake filling up a great Rift Valley, and the south-western extremity of Arabia have been joined across the narrow straits of Bab-al-Mandib to Somaliland. There is an Arab tradition that in the remote past these straits were formed by a series of earthquakes and land-slides. But if this were the case why is not the west of Arabia, in fertile, well-watered regions, more “African” in its mammalian, bird, and insect fauna? Arabia is a great enigma still in these questions of geographical distribution. It would be convenient to regard it as the evolutionary area of the negro, if, for example, there were any evidence of a positive character—as there is in southern Persia—to show that it was ever the home of a negro race in ancient times. But there is no such evidence, and its present negro or negroid population only dates from the trade in negro slaves which began about the commencement of the Christian era, and flourished exceedingly after the eruption of Islam.

“Lemuria”—the hypothetical isthmus which once united Madagascar and East Africa with India and Ceylon—could not have been the negro’s birth-place, as some have suggested, inasmuch as it ceased to exist in the early Tertiaries, long before Man had been evolved.