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316 view to the primates alone, respecting whose Asiatic origin there is no dissenting voice among those competent to speak. The most convenient presentation of the subject is in Matthew's paper on "Climate and Evolution," whose sketch map we reproduce here, together with the chronological scale essential to its interpretation. From this we see, in a general way, how the many diverse forms of primates have swarmed out of the Old World, one after the other. We have, therefore, no alternative but to conclude that the same factors controlling the dispersion of the whole division of primates apply also to man, and that his dispersion will, in the main, follow the same beaten tracks. With this as a point of departure, it is not very difficult to form a satisfactory statement of the order and direction of dispersion for the known species and varieties of hominidæ.

When we consider the map in Fig. 97, it appears that the New World is geographically more remote than either Africa, Europe, or the insular area, and has but one point of contact, but that point is in direct line with the assumed center of dispersion. On mere geographical grounds, we should locate the extremes of expansion in Patagonia, Greenland, Cape Colony, Ceylon, and Tasmania. To this list may also be added the extreme western parts of Europe, as the Canaries and British Isles. These are veritable blind alleys in which primitive man was ultimately brought up short and where some of his descendants are still marking time. It so happens, however, that the fluctuating polar ice cap hovers over the single narrow bridge to the New World and the part it has played in the story of the primates is truly wonderful. The reader familiar with the recent literature on Paleolithic man need not be told that the pulsation of this ice cap is proving the only reliable time clock for human culture. At four intervals, at least, this ice field crept down into North America and into the Old World, each time greatly modifying the distribution of mammalian life.

Though we now have a fairly complete outline of man's relation to these events in Europe, we are quite in the dark as to what happened in Asia and America. The United States