Beringia

The initial habitation of the Americas has gotten a lot of press attention in the last couple of weeks.

National Geographic gave us a report on skeletal remains from an underwater cave in Yucatan, called Hoyo Negro ("Skull in underwater cave may be earliest trace of First Americans"). There's no date yet for the human remains, which are associated with megafauna -- but no reason at all to go with the news story's "15,000-20,000 years ago," that's just sensationalism.

Last week, Science published a report on a child cremation burial from Alaska dating to 11,500 years ago [1]. In the paper, Ben Potter and colleagues compare the Alaskan site (Upward Sun River Site -- USRS) to a site in the western part of the region that was once Beringia, but now is on the Siberian side of the Bering Strait:

Only one other ancient burial site is known for Beringia: Ushki Lake 1, in Kamchatka, Russia (34–37) (Fig. 1). Ushki Lake 1, Level 7 (Ushki L7) (~13,000 cal yr B.P.) contained an adult burial associated with bone beads in a rock-lined ochre-filled pit separated from the house structures. Ushki Lake 1, Level 6 (Ushki L6) (~12,000 cal yr B.P.) is roughly contemporaneous with USRS Component 3 and contains two unburned burials of children within two separate houses (35, 36). One child burial contained ochre, a pendant, a mat of lemming incisors, and numerous microblades and wedge-shaped cores (the second burial is undescribed) (35). Thus, the USRS burial context is more like Ushki L6 than L7. This replicates technological linkages between continents: Diuktai Culture of Ushki L6 is comparable with the Denali Complex, which dominates the record from 12,000 to 6000 cal yr B.P. in interior eastern Beringia (24, 38), whereas the Ushki Culture of Ushki L7, associated with stemmed points and lacking microblades, arguably has no direct counterpart in North America [(39), but see (34)].

That reference to the stemmed points becomes important in the next paper, published in Science this week by Erlandson and colleagues [2]. The report is a description of a mixed archaeological assemblage from the Channel Islands of California, with a few artifacts from a shell midden dating to 12,200 BP [2]. The date is not all that early, not earlier than Clovis. It's interesting because it seems to further the evidence for a distinct archaeological tradition in the West, with inland occurrence and possible connections to South America.

If Arlington Springs [skeletal remains dating to 13,000 BP] is included, the earliest Paleocoastal Channel Island sites are contemporary with Clovis and Folsom sites of the continental interior (6, 8, 20). The island sites provide evidence for Terminal Pleistocene seafaring, island colonization, and a diversified maritime economy, adding to the variability of Paleoindian adaptations in the Americas. The stemmed points and crescents dated as early as 12,200 cal BP link these early island assemblages to those found in interior Western Pluvial Lakes Tradition (WPLT) sites found around many lakes and marshes in North America’s Far West (15). Stemmed point fragments have also been recovered in the basal levels of Paisley Caves, dated to ~14,300 cal BP (21), and the Paleocoastal stemmed points and crescents from the Channel Islands seem unlikely to be descended from Clovis. Such WPLT assemblages may provide a logical technological link among Terminal Pleistocene stemmed point traditions of Northeast Asia (22), the Pacific Northwest, and possibly early stemmed point traditions widely distributed in South America (23).

The Clovis industry was a very short-term phenomenon, and spread across an area of North America that makes an unlikely link to the rest of the Americas. Seems more like a cul-de-sac in some sense. Movement down the western coast makes more sense, but the cultural traces of early Paleoindians have been scarce. But these seem to be adding up to something -- the stemmed point in Paisley, now the earliest site with biological evidence of humans in the Americas, is interesting in this regard. It's not a radical revision of the timeline; this is all about a relatively short period of pre-Clovis occupation, maybe 2000 years as we understand it now. The research is beginning to make more connections among early occurrences, making them seem more like a system than like outliers.

UPDATE (2011-03-07): A reader (who should know) chides me for describing Clovis as a "cul-de-sac" industry, noting the distribution of fluted points is much more widespread. Another reader expresses some interest in the ecological setting of these stemmed points across the broader West. I will return to the issue soon, which deserves a fuller review than this.

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