of India, who were derived from the Mongols of the Interior.
The conclusion to which this discussion leads is that the connection between the Heartland, and especially its more open western regions of Iran, Turkestan, and Siberia, is much more intimate with Europe and Arabia than it is with China and India, or yet with the Southern Heartland of Africa. The strong natural frontiers of the Sahara Desert and the Tibetan Heights have no equivalent where the Northern Heartland merges with Arabia and Europe. The close connection of these three regions is well typified by that geographical formula into which it was attempted to crystallise. just now certain essential aspects of Mesopotamian and Syrian history; the ploughmen of Mesopotamia and Syria have always been exposed to descents of the horsemen from the Heartland, of the camel-men from Arabia, and of the shipmen from Europe. None the less—and indeed just because of its more transitional character—the boundary between the Heartland on the one hand, and Arabia and Europe on the other, is worth following with some care.
