456 POPULAR SCIENCE MONTHLY. 



Entry into the fourth racial region was not from Tndo-Malaysia 

 but from the Arctic peninsulas of the eastern hemisphere. During the 

 period of dispersion, continuous connections probably existed along 

 these high latitudes, joining America with northwest Europe, on the 

 one hand, and with northeast Asia, on the other. It was possible, 

 therefore, during these early ages, for dolichocephalic Mediterranean 

 people to continue the course of their northwesterly migrations until 

 they reached the Atlantic shores of the new world; and for brachy- 

 cephalic Asiatics to pursue their way northeastward until they came 

 to the Pacific coast of the continent. That the western hemisphere 

 was originally occupied in this manner by emigrants from Europe and 

 Afeia appears probable from the prevalence among the American abo- 

 rigines of the long-head type in the east and the broad-head type in 

 the west. The incursion along the Atlantic could not have lasted as 

 long as that proceeding by way of the Pacific, for the ancient land-bridge 

 joining northwest Europe with northeast America was broken long 

 before the prehistoric period, and the islands left between were too far 

 apart to afford further access from this direction. On the Pacific 

 side, however, the old miocene bridge, with its temporary glacial ex- 

 tensions, probably endured until quaternary times, and after this, ap- 

 proaches still remained across the narrow Behring strait and along 

 the Aleutian island chain. We should think of Asia, therefore, as the 

 source of the main stream of migration that spread southeastwards 

 over the new world. 



In these early days, before the knowledge of ocean navigation, 

 America was not as now a Durchgangsland, but rather a cul-de-sac. 

 There was entry on either side from the north, but no exit in any 

 other direction. The aboriginal people pouring in from above must, 

 therefore, have been pushed down by the later comers through the 

 constricted central space, like the sands in an hourglass, to spread 

 out along the equator and become contracted again in the apex of the 

 continent. Moreover, as the main stream of migration proceeded from 

 Asia, the emigrants from Europe were probably confined from the first 

 to the eastern edge of the hemisphere. Cut off completely from fur- 

 ther contact with other people, the American aborigines, long-heads 

 and round-heads alike, were henceforth subjected to the influences of 

 their new surroundings and modified accordingly. 



Geographically speaking, the American continent differs from the 

 other regions of the earth, and at the same time possesses certain posi- 

 tive characteristics of its own. This isolation of the western hemi- 

 sphere, taken together with such environmental uniformity as exists 

 within its borders, had the effect of differentiating the aboriginal in- 

 habitants from their European and Asiatic ancestors and blending 

 them gradually into one racial variety, possessing pronounced Oriental 

 affinities. 



