Concluding Remarks and a New Agenda

When did humans colonize the Americas? From where did they come and what routes did they take? These questions have gripped scientists for decades, but until recently answers have proven difficult to find. Current genetic evidence implies dispersal from a single Siberian population toward the Bering Land Bridge no earlier than about 30,000 years ago (and possibly after 22,000 years ago), then migration from Beringia to the Americas sometime after 16,500 years ago. The archaeological records of Siberia and Beringia generally support these findings, as do archaeological sites in North and South America dating to as early as 15,000 years ago. If this is the time of colonization, geological data from western Canada suggest that humans dispersed along the recently deglaciated Pacific coastline.

Three different sorts of bifacial tools-by-products of the shaping process, cores, and long use-life tools-are used to consider the role mobility plays in producing variability in hunter-gatherer lithic technologies. The relations among tool roles, raw-material distribution, and mobility as well as the archaeological consequences of the different roles are key factors. An examination of temporal trends in the use of bifacial implements in the Carson Sink of western Nevada shows how the proposed perspective on lithic technology can help to elucidate change in mobility strategies. A shift from the use of bifaces as cores to an infrequent use of bifaces as tools suggests a shift from logistical to short-term residential use of the raw-material-poor Carson Sink; a later shift to the use of small, frequently unifacial, nonresharpenable points may indicate a shift to target-specific hunting strategies.