182. The Spread Over Two Continents
Before them lay fifteen million miles of tundra, forest, plains, sea coast, desert, savannah, jungle, and plateaux, rich in this or that food, with no occupant to dispute possession or block travel but bear, wolf, puma, and jaguar—timid beasts compared with those of the Old World. So the immigrants pushed across the breadth of the continent and down its length, entered the tropics in Mexico, defiled through Panama—and a second continent stretched before them. How long it took the first wanderers to diffuse themselves from Alaska to the Strait of Magellan, it is impossible to say. Perhaps a couple of thousand years, perhaps only a few hundred. Curiosity, the desire to see, are strong in men if fear imposes no restraints.
Sooner or later, at any rate, they were living throughout both continents. The advance guard had long lost knowledge of the rear, if indeed the rear did not arrive until after the advance could progress no farther. When the Caucasian discovered America he might have commenced at Cape Horn, gone on to a people whose very existence was unknown to those at his starting point, and repeated the step a dozen times until his journey brought him to the Arctic. Before the rise of the empires of Mexico and Peru the number of links in the chain ignorant of each other would have been greater. The moving bands of the primitive first-comers no doubt lost touch with each other quickly in even shorter stretches. Thus diversities of speech, of mode of life, would become established. A family of brothers might become dominant in a band through the number of their descendants and so color the somatic type of the group, which in turn, favored by fortune and expanding, might lay the hereditary foundation for a sub-racial variety.
Movements of population continued to occur until the present. The maps of speech stocks previously presented (Figs. [14], [15]) prove that distant migrations took place after great groups like Athabascan, Algonkin, Uto-Aztecan, Arawak, Tupi, had each lived in compact coherence long enough to establish a well defined language. But so far as these more recent migrations can be traced from speech, they no longer trended prevailingly from north to south and west to east as the first general diffusion must have moved, but shifted in the greatest variety of direction. They are a sort of boiling of the kettle, not a downhill flow. They relieved internal strains and vacillated back and forth with circumstances; they represented no drift like the first occupation. Much of their story may ultimately be worked out and provide a national history of pre-Columbian America. But the effect of these later pressures and expansions and wanderings on the culture development of the New World as a whole is likely to have been relatively slight.