[Sidenote:  The Atlantic abyss.]

The long Atlantic rift between the Eastern and Western Hemispheres, which was such a potent factor in the primitive retardation of Africa is, from the standpoint of anthropo-geography, the most important feature in the distribution of the land-masses over the globe.  Not till the discovery of America bridged this abyss did the known world become a girdle round the earth.  Except the Norse ventures to the American continent by way of Iceland and Greenland between 1000 and 1347, no account of pre-Columbian intercourse between the two shores of the Atlantic has ever been substantiated.  Columbus found the opposite land unfamiliar in race as in culture.  He described the people as neither whites nor blacks, the two ethnic types which he knew on the eastern side of the Atlantic abyss.  He and his successors found in the Americas only a Stone Age culture, a stage already outgrown by Europe and Africa.  These continents from Lapland to the Hottentot country were using iron.  Prior to the voyage of the great Genoese, Europe gave nothing to America and received nothing from it, except the Gulf Stream’s scanty cargo of driftwood stranded on bleak Icelandic shores.  The Tertiary land-bridge across the North Atlantic between Norway and Greenland may possibly have guided a pre-Caucasic migration to America and given that continent part of its aboriginal population.[756] However, no trace of any European stock remains.

[Sidenote:  Atlantic islands uninhabited.]

The collapse of the bridge at the close of the Glacial Epoch left the Atlantic abyss effectually dividing the two hemispheres.  Its islands, few and far between, were helpless to maintain intercourse between the opposite shores; this is proven by the fact that all of them from Greenland to Tristan da Cunha, excepting only the Canaries, were uninhabited at the time of their discovery.  History records when the first bold voyagers came upon them in that unmarked waste of waters, and gave them their first occupants.  The political upheavals of Norway in King Harfagr’s time (872) sent to the Faroes and Iceland their first settlers, though these islands were previously known to the Celts of Ireland.  The Norse colonists who went to Greenland in the year 1000 seem to have been the first regular settlers on those inhospitable coasts.  They found no native inhabitants, but numerous abandoned dwellings, fragments of boats and stone implements,[757] which doubtless recorded the intermittent voyages thither of the Eskimo, preliminary to permanent occupation.  The Scandinavians did not encounter natives on the island till the 12th century, when Greenland probably received its first Eskimo immigration.[758]

[Sidenote:  Geographical character of the Pacific.]