American Association for the Advancement of Science
How and when human populations first arrived and settled in the Americas remains debated. A longstanding and influential hypothesis proposes that travelers initially entered North America and parts beyond from eastern Beringia, by way of a deglaciated ice-free corridor that separated the Cordilleran and Laurentide ice sheets approximately 14,800 years ago. However, a small but growing body of research has shown that human populations were present and likely well-established south of the Late Pleistocene ice sheets long before such a passage; its proponents hypothesize a Pacific coastal migration route.
Loren Davis and colleagues present new findings from Cooper's Ferry that provide evidence of repeated occupation beginning between 16,560 to 15,280 years ago. Artifacts recovered from the site's earliest contexts indicate the use of unfluted and stemmed stone projectile point technologies before the use of fluted, broad-based points of the widespread Clovis Paleoindian Tradition.
According to Davis et al., the age, design and manufacture of Cooper's Ferry's distinctive stemmed points closely resemble features of artifacts found in Late Pleistocene archeological sites in northeastern Asia. The results suggest an initial migration along the Pacific Coast more than 16,000 years ago.