In this model, the first Americans were the makers of the Clovis projectile points, who entered North America from northeast Asia across the Bering Land Bridge sometime around 13,000 to 14,000 years ago and spread rapidly through the interior of the continent, following the herbivore herds of the late Pleistocene.

This model implied that the Pacific coast of North America was not the route — that interior corridors through the retreating ice sheets were where the first Americans moved.

By the time the Arlington Springs revision was published, the Clovis First model was already under pressure from multiple directions.

Monte Verde, a site in southern Chile dated to approximately 14,500 to 14,800 years ago — older than any Clovis site — had been exhaustively verified after a long period of controversy and had forced the conclusion that people were in the southern tip of South America before Clovis appeared in North America.

If people were in southern Chile by 14,500 years ago, they could not have arrived via an interior route through North America after Clovis appeared around 13,000 years ago — the dates did not permit enough time for the population to reach Chile.