THE DESCENT OF MAN. 375 



Atlantic and Pacific routes of migration were continued along the 

 northern latitudes into the Western Hemisphere. Toward the north- 

 west, the British Isles then formed an integral part of the European 

 continent, and from this peninsula, land-connections were in all prob- 

 ability extended through Iceland and Greenland to America. In the 

 far northeast, Asia was likewise joined with America by what geolo- 

 gists call the Miocene bridge, which probably lasted into quaternary 

 times ; and after the Behring strait finally broke through, the Aleutian 

 island chain still linked the two continents together along the Pacific. 

 As far as climate and topography were concerned, during these 

 interglacial epochs there was nothing, therefore, to prevent the Medi- 

 terranean and Malaysian emigrants from pushing northwestward 

 through Europe and northeastward though Asia into America. 



As the glaciers advanced successively from the arctic and antarctic 

 regions, the climate and topography of the Northern and Southern 

 Hemispheres varied in this way at least three times. After the third 

 glacial epoch, however, the changes were less marked, until towards the 

 close of the ice age, the configuration of the earth gradually assumed 

 its historic form and the globe became divided as at present into tem- 

 perature zones. The possibilities of dispersion during the glacial, inter- 

 glacial and post-glacial periods may, accordingly, be generalized as fol- 

 lows: Each time the Northern Hemisphere was glaciated, the migra- 

 tions of men must have been confined for the most part within the 

 Indo-Mediterranean-Malaysian belt and the southern peninsulas of the 

 Old World. During the genial epochs that intervened between the 

 three great glacial movements from the north, the continental area was 

 open to incursion on either side, the climate of the Northern Hemisphere 

 was everywhere equable, and the topographic conditions were such as 

 to encourage migration along the Atlantic and Pacific shores of the 

 Eurasian continent into the arctic peninsulas of the New World. As 

 the arctic glaciers became more and more restricted to the northern 

 regions, primeval men were probably able to hold their own in the 

 continental area and migrate east and west across Eurasia. But after 

 the third glacial epoch, if not before, the Atlantic land-bridge was 

 broken; so that henceforth access to America was only possible along 

 the Pacific, by means of the Aleutian island chain. 



Cave deposits, kitchen-middens and fossil remains mark the course 

 of the dispersion of mankind in these different directions. The 

 aboriginal inhabitants of the now separated continents and isolated 

 islands of the globe also preserve certain distinguishing characteristics 

 by which the lines of their respective ancestries can be traced back 

 along these several routes to more or less definite points of departure 

 about the Indo-Malaysian abode. There is archeological and ethno- 

 logical evidence, therefore, to show that primeval men migrated 



