The Tennessee Division of Archaeology documented an extensive Paleoindian lithic quarry and workshop at the Sinclair site in Tennessee in 2008. We present the first detailed description of the lithic assemblage here, which focuses on aspects of its prismatic blade technology. Quantitative and qualitative attributes of 117 blades are assessed to characterize the assemblage and investigate human behaviors related to its formation. We then compare the blades from Sinclair to other blade assemblages. Blades at Clovis workshop sites are large and generally unstandardized. Mobile Clovis bands selected long, highly standardized blades from workshop sites, cached them as resource insurance, and crafted and used them as tools at campsites. The prismatic blade assemblage at Sinclair and other sites throughout the Midsouth suggests that this region played an important role in the development of prismatic blade technology at the end of the Pleistocene.

El Fin del Mundo is an archaeological site in Sonora, northwest Mexico, that contains a buried Clovis megafauna kill in a lowland area and concentrations of Clovis and later lithic materials scattered on the deflated surface of the surrounding uplands. The Clovis lithic assemblage from the site, identified by its technological and typological features, has been classified into three modes: bifaces, unifaces, and blades. The kill locality only contains Clovis points, whereas the assemblage from the uplands includes multiple bifaces reflecting diverse stages of the manufacture process from blank production to finished, highly reduced, and discarded broken Clovis points, numerous end scrapers, and blades and blade manufacture byproducts. This assemblage is indicative of a campsite where stone tool production and possibly other domestic tasks took place. In addition, a rhyolite outcrop near both the campsite and the kill was intensively exploited, as reflected in the high proportion of this raw material in the Clovis assemblage. Unequivocal association of the kill locality and the campsite is not confirmed; however, the configuration of the site indicates that the campsite was established in uplands near locations with water, game, and lithic resources.

An enduring problem in North American archaeology concerns the nature of the transition between the Clovis and Folsom Paleoindian complexes in the West. Traditional models indicate a temporal hiatus between the two complexes implying that Folsom was a population replacement for Clovis. Alternatively, if Folsom was an innovation that occurred within Clovis populations and subsequently spread, we would expect to see a temporal overlap. Here, we test these hypotheses using high-quality radiocarbon dates and Bayesian statistics to infer the temporal boundaries of the complexes. We show that the Folsom complex initially appears between 12,900 and 12,740 cal BP, whereas Clovis disappears between 12,720 and12,490 cal BP. Therefore, Folsom may have appeared about 200 years before Clovis disappeared, and so the two complexes likely co-occurred in the West for nearly eight generations. This finding suggests that Folsom was a successful adaptive innovation that diffused through the western Clovis population, eventually going to fixation over multiple generations.

In 2019, we launched the Northern Arizona Paleoindian Project to expand on findings from the Rock Art Ranch (RAR) Research Experiences for Undergraduates (REU; NSF#1262184). The REU recovered 24 Paleoindian artifacts in association with drainages. Expansion of the research required mitigation of the patchwork landownership in the area, which encouraged a collector-collaboration model following Pitblado (2014) and Douglass et alia (2017). We held public events in collaboration with a network of agencies, avocational groups, collectors, and landowners to assess potential for Paleoindian archaeology in the area. In March 2020, however, the COVID-19 pandemic halted our efforts, allowing us to evaluate our project and practice. We find that tapping into existing local networks of responsible resource stewards (RRS) can greatly accelerate project development. We also find that private collections are endangered, and preserving this portion of the archaeological record requires documentation and long-term curation. Most importantly, we find that archaeologists working with collectors are uniquely positioned to build bridges between Indigenous communities, RRS, and professional archaeologists to help stabilize legacy collections and that this focus should drive collector-collaboration research design. Ultimately, the project must move toward a community-based participatory research design to seek equitable and culturally appropriate curation plans for local legacy collections.

Diez-Martin and colleagues (2021) experimentally reduce four bifaces and argue that the resultant flakes are smaller and less uniform than those found at the Welling site (33Co2). Welling is an early Paleoindian (Clovis) site excavated by Olaf Prufer over 50 years ago. Based on the experiment, the authors conclude that the site was a “collector-like” base camp and that our previous interpretation must be incorrect. Here, we argue that Diez-Martin and colleagues have mischaracterized our conclusion regarding the purpose of the site, and may have insufficiently addressed data that detract from their new interpretation.

Seeman, Morris, and Summers misrepresent or misunderstand the arguments we have made, as well as their own previous work. Here, we correct these inaccuracies. We also reiterate our support for hypothesis-driven and evidence-based research.

The extent to which Clovis peoples hunted proboscideans is debated. Convention requires that for a proboscidean butchery site to be accepted, contemporaneous artifacts must be spatially associated with faunal remains, and there must be evidence of use of the remains. Fourteen sites in North America currently meet those criteria; at least 31 do not. While these are reasonable requirements for avoiding false positives, such an approach risks identifying false negatives—rejecting spatial associations that are systemic associations. Given the known distributions of Clovis and proboscidean sites, how likely is it that artifacts are coincidentally associated with proboscidean remains? Conversely, how many spatial associations could be unrecognized butchery sites? To answer these questions, we simulated chance associations by plotting empirically informed densities and sizes of archaeological and proboscidean sites on simulated landscapes in which people and animals are (a) uniformly distributed and (b) tethered to water sources. The simulated frequencies of coincidental associations were compared to the observed frequency of co-occurrences. Our results suggest that of the 31 indeterminate empirical associations, at least 17 and as many as 26 are likely systemic associations, more than doubling previous estimates and revealing a greater role of humans in Pleistocene proboscidean exploitation than previously recognized.

Archaeological collections are foundational to the discipline. Yet, researchers who study curated assemblages can face challenges. Here, we show how experimental archaeology can play a vital role in the interpretation of old archaeological collections. The Welling site, in Coshocton County, Ohio, is a multicomponent, stratified site with a substantial Clovis component in its lower levels. Using experimental flaked stone replication, we create an analog model of a “pure” Clovis bifacial debitage assemblage, as might be found at a lithic workshop. We predicted that if the Welling Clovis debitage assemblage was representative of a lithic workshop, then it would be similar to the experimental model. If the debitage assemblage was representative of a base camp, however, then it would be significantly different from the model because Clovis people would have been using, transporting, resharpening, rejuvenating, and recycling the debitage—all activities that would modify a “pure” Clovis bifacial debitage assemblage. Our statistical analyses supported the latter prediction. Overall, our study illustrates how productive the integration of experimental and archaeological data can be, and it emphasizes how important the curation and accessibility of both archaeological and experimental collections are to the discipline.

A single radiocarbon date derived from the Buhl burial in south-central Idaho has frequently been used as a data point for the interpretation of the Western Stemmed Tradition (WST) chronology and technology because of the stemmed biface found in situ with the human remains. AMS dating of bone collagen in 1991 produced an age of 10,675 ± 95 14C BP, immediately postdating the most widely accepted age range for Clovis. The Buhl burial has been cited as evidence that stemmed point technology may have overlapped with Clovis technology in the Intermountain West. We discuss concerns about the radiocarbon date, arguing that even at face value, the calibrated date has minimal overlap with Clovis at the 95.4% range. Furthermore, the C:N ratio of 3.69 in the analyzed collagen is outside of the typical range for well-preserved samples, indicating a postdepositional change in carbon composition, which may make the date erroneously older or younger than the age of the skeleton. Finally, the potential dietary incorporation of small amounts of anadromous fish may indicate that the burial is younger than traditionally accepted. For these reasons, we argue that the Buhl burial cannot be used as evidence of overlap between WST and Clovis.

Archaeologists have long subjected Clovis megafauna kill/scavenge sites to the highest level of scrutiny. In 1987, a Columbian mammoth (Mammuthus columbi) was found in spatial association with a small artifact assemblage in Converse County, Wyoming. However, due to the small tool assemblage, limited nature of the excavations, and questions about the security of the association between the artifacts and mammoth remains, the site was never included in summaries of human-killed/scavenged megafauna in North America. Here we present the results of four field seasons of new excavations at the La Prele Mammoth site that confirm the presence of an associated cultural occupation based on geologic context, artifact attributes, spatial distributions, protein residue analysis, and lithic microwear analysis. This new work identified a more extensive cultural occupation including the presence of multiple discrete artifact clusters in close proximity to the mammoth bone bed. This study confirms the presence of a second Clovis mammoth kill/scavenge site in Wyoming and shows the value in revisiting proposed terminal Pleistocene kill/scavenge sites.

Hunter-gatherer societies held sway in midwestern North America for at least 11,000 years. Those at the end of this period were more complex and less mobile, and they supported larger populations than those at the beginning, but there are relatively few general conceptions as to when and how this took place. Here we examine the fit of gradual, one-way social change as it relates to the size and shape of lithic supply zones for Upper Mercer and Flint Ridge flint as well as the inflow of exotic materials. Our results show no singular cline either in the size of successive lithic supply zones or in the inflow of exotic materials. Hunter-gatherer societies can make remarkable behavioral changes through time and not necessarily in any consistent (unilineal) direction. Such differences impose more contingency—and less directionality—into particular historical sequences.

Immense late Wisconsin floods from glacial Lake Missoula drowned the Wenatchee reach of Washington's Columbia valley by different routes. The earliest debacles, nearly 19,000 cal yr BP, raged 335 m deep down the Columbia and built high Pangborn bar at Wenatchee. As advancing ice blocked the northwest of Columbia valley, several giant floods descended Moses Coulee and backflooded up the Columbia past Wenatchee. Ice then blocked Moses Coulee, and Grand Coulee to Quincy basin became the westmost floodway. From Quincy basin many Missoula floods backflowed 50 km upvalley to Wenatchee 18,000 to 15,500 years ago. Receding ice dammed glacial Lake Columbia centuries more—till it burst about 15,000 years ago. After Glacier Peak ashfall about 13,600 years ago, smaller great flood(s) swept down the Columbia from glacial Lake Kootenay in British Columbia. The East Wenatchee cache of huge fluted Clovis points had been laid atop Pangborn bar after the Glacier Peak ashfall, then buried by loess. Clovis people came five and a half millennia after the early gigantic Missoula floods, two and a half millennia after the last small Missoula flood, and two millennia after the glacial Lake Columbia flood. People likely saw outburst flood(s) from glacial Lake Kootenay.

The paleoenvironments of late Pleistocene and early Holocene time on the Southern High Plains have been studied for decades, but regionally extensive or long-term, easily recoverable proxy climate indicators are difficult to find. The stratigraphy of valley fill and upland eolian deposits and stable-carbon isotope data, in addition to geographically limited paleontological data, now provide clues to the environment during this time, which includes the earliest, or Paleoindian period (∼11,200–8000 14C yr B.P.) of human occupation. During the Clovis occupation (∼11,200–10,900 14C yr B.P.), valleys contained perennial streams. This was followed in Folsom time (10,900–10,200 14C yr B.P.) by an abrupt change to lakes and ponds (with water levels fluctuating between several meters depth and no surface water) and marshes and accumulation of sheet sands on uplands, starting the earliest phase of construction of the regional dune fields. These changing conditions indicate a shift from relatively wetter to relatively drier conditions with episodic drought. Stable-C isotopes further indicate that warming characterized the Clovis–Folsom transition. During the rest of the Paleoindian period the environment was relatively cool but fluctuated between wetter and drier conditions with an overall trend toward drying that resulted in further enlargement of the dune fields and culminated in the warm, dry Altithermal beginning ∼8000 14C yr B.P. Clovis time probably was the wettest of any Paleoindian period in terms of runoff and spring discharge. The Folsom period was drier and was the earliest episode of regional wind erosion and eolian deposition and may have been the warmest of Paleoindian times. Evidence of a previously hypothesized “Clovis drought” in this region is sparse.

Discovery of the Monte Verde archeological site in Chile overturned the previous consensus that the first Americans into the New World from Asia were the makers of Clovis projectile points, and rejuvenated the hypothesis that migration through the Americas occurred largely on portions of the Pacific continental shelf exposed by Pleistocene drawdown in eustatic sea level. The postulate of travel along a paleoshoreline now hidden underwater is an attractive means to posit pre-Clovis human movement southward from Beringia to Chile without leaving traces of migration onshore. Geologic analyses of the Pleistocene paleoenvironment at Monte Verde and of the morphology of the potential migration route along the continental shelf raise questions that have not been fully addressed. The periglacial setting of Monte Verde may call its antiquity into question and the narrowness of the Pacific continental shelf of the Americas makes it unlikely that people could travel the length of the Americas without impacting ground still onshore and no farther inland than Monte Verde itself. Geological perspectives on Monte Verde and coastal migration jointly suggest that the Clovis-first hypothesis for peopling the New World may have been abandoned prematurely.

We investigate seasonal variations in the diet and drinking water of four Great Lakes mastodon (Mammut americanum) specimens using stable isotope analysis of serially sampled inner-enamel bioapatite structural carbonate (δ13Csc, δ18Osc), and previously published bulk analyses. Isotopic analyses and thin section measurements showed that mastodon tooth enamel extension rates (~ 12–4 mm/yr, decreasing toward the cervix) were lower than those of mammoths or modern elephants. Mastodons had distinct and highly regular seasonal variations in δ13Csc and δ18Osc, which we interpret in the context of local glacial history and vegetation changes. Seasonal variations in δ18O were large but variations in δ13C were small, and may have been obscured if coarser sampling methods than our inner-enamel sampling approach were used. Thus, our approach may be particularly useful for understanding relatively small seasonal changes in δ13C within C3 environments. The seasonal patterns, though not entirely conclusive, suggest that the Ontario mastodons did not migrate over very long distances. Rather, the climate and seasonal dietary patterns of mastodons within the region changed over time, from ~ 12,400 to 10,400 14C yr BP (~ 15,000 – 12,000 cal yr BP). Insights gained using these methods can contribute to a better understanding of megafaunal extinctions and Paleoamerican lifeways.

The recent proposal that North America was first settled by Upper Palaeolithic people from Europe who crossed the Atlantic along the edge of the Arctic ice sheet has generated considerable controversy. Here Michael O'Brien and colleagues challenge the evidence that has been presented in support of that hypothesis. There follows a response by Dennis Stanford and Bruce Bradley, and a closing reply from O'Brien et al.