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Evidence of mastodon bone modifications for marrow extraction and/or tool production, found in the presence of hammerstones and anvils that showed use-wear and impact marks, suggest the presence of Homo in North America around 130 thousand years ago. America's oldest human activity Around 130,000 years ago, a mastodon died near what is now San Diego, California. Although this seems uncontroversial, Thomas Deméré and colleagues present evidence that the carcass had been modified by human beings. Stone hammers and anvils were found alongside mammoth bones and teeth that show signs of having been broken by percussion, presumably to extract bone marrow. Dating the site has been problematic because the bones preserved too little collagen for radiocarbon dating, and optically stimulated luminescence dating put the age at over 60,000–70,000 years. Dates based on the decay of uranium, constrained by the movement of uranium between the environment and the bone, now give an age of around 130,000 years. If confirmed, this would extend tenfold the time that human beings are known to have been present in the Americas and predate the time that modern humans are thought to have first left Africa. The identity of the hominin species—if any—remains unknown. The earliest dispersal of humans into North America is a contentious subject, and proposed early sites are required to meet the following criteria for acceptance: (1) archaeological evidence is found in a clearly defined and undisturbed geologic context; (2) age is determined by reliable radiometric dating; (3) multiple lines of evidence from interdisciplinary studies provide consistent results; and (4) unquestionable artefacts are found in primary context 1 , 2 . Here we describe the Cerutti Mastodon (CM) site, an archaeological site from the early late Pleistocene epoch, where in situ hammerstones and stone anvils occur in spatio-temporal association with fragmentary remains of a single mastodon ( Mammut americanum ). The CM site contains spiral-fractured bone and molar fragments, indicating that breakage occured while fresh. Several of these fragments also preserve evidence of percussion. The occurrence and distribution of bone, molar and stone refits suggest that breakage occurred at the site of burial. Five large cobbles (hammerstones and anvils) in the CM bone bed display use-wear and impact marks, and are hydraulically anomalous relative to the low-energy context of the enclosing sandy silt stratum. 230 Th/U radiometric analysis of multiple bone specimens using diffusion–adsorption–decay dating models indicates a burial date of 130.7 ± 9.4 thousand years ago. These findings confirm the presence of an unidentified species of Homo at the CM site during the last interglacial period (MIS 5e; early late Pleistocene), indicating that humans with manual dexterity and the experiential knowledge to use hammerstones and anvils processed mastodon limb bones for marrow extraction and/or raw material for tool production. Systematic proboscidean bone reduction, evident at the CM site, fits within a broader pattern of Palaeolithic bone percussion technology in Africa 3 , 4 , 5 , 6 , Eurasia 7 , 8 , 9 and North America 10 , 11 , 12 . The CM site is, to our knowledge, the oldest in situ , well-documented archaeological site in North America and, as such, substantially revises the timing of arrival of Homo into the Americas.

The evidence reported in Holen et al. (2017) for hominin activity at the Cerutti Mastodon site is being intensively critiqued by many of our colleagues, but often with little regard for the cumulative meaning or the contextual data that support our interpretation of cultural bone and stone modification at the site. Magnani et al. (2019) characterise our bone-breakage experiments as pilot studies, or first-generation experiments, and as such, argue them to be insufficient in their own right to overturn previous research on hominin migration. While we acknowledge the limits imposed by qualitative data and the potential gains offered by quantitative, laboratory experimentation, much has been learned from these field experiments—including insights into processes used in the past and phenomena worthy of further investigation. We (Holen et al. 2017: supplementary information) state that the aim of the actualistic experiments was to replicate the process by which hominins, for at least 1.5 million years, used hammerstones to break fresh proboscidean limb bone to harvest and quarry bone for nutritive value and for tool manufacture..

Proboscidean limb bones discovered in Yukon during the 1960s and 1970s exhibit fracture patterns, notches, and bone flakes that are characteristic of percussion. Because of the unique properties of thick cortical proboscidean bone (probably woolly mammoth Mammuthus primigenius or less likely American mastodon Mammut americanum), some researchers hypothesized that these fracture patterns represent intentional hammerstone modification by humans for marrow extraction and bone tool production. As such, these fracture patterns represent evidence of early human dispersal into Eastern Beringia. Radiocarbon dating in the late 1980s indicated that the bone breakage occurred between about 25 000 and 40 000 radiocarbon years before present (14C yr BP). We report 11 new radiocarbon ages using ultra-filtration methods on a different sample of similarly fractured and flaked bones from Yukon. Only two of the radiocarbon ages fall within the expected range of 25 000 to 40 000 14C yr BP. Six other ages are non-finite, with five being more than 49 100 14C yr BP. Three finite ages range between 46 500 and 50 500 14C yr BP with large standard deviations, and these ages may also be non-finite. Two testable hypotheses to explain the observed breakage patterns were developed, the first being that humans broke the bones and the second that some presently unknown geological process broke the bones. Further research is needed to test these two hypotheses. Des ossements de membres de proboscidiens découverts au Yukon dans les années 1960 et 1970 présentent des structures de fractures, des encoches et des traces d'enlèvements d'éclats caractéristiques de la percussion. En raison des propriétés uniques de l'os cortical proboscidien (provenant probablement d'un mammouth laineux Mammuthus primigenius ou, ce qui est moins probable, d'un mastodonte américain Mammut americanum), certains chercheurs ont avancé une hypothèse selon laquelle ces structures représentent des modifications intentionnelles faites au marteau en pierre par des humains, à des fins d'extraction de la moelle et de production d'outils en os. En tant que telles, ces structures de fractures témoignent de la présence ancienne d'humains dans l'est de la Béringie. Vers la fin des années 1980, la datation au radiocarbone a permis de déterminer que les fractures auraient été faites il y a environ 25 000 à 40 000 années radiocarbones avant le présent (14C ans BP). Nous faisons état de 11 nouveaux âges au radiocarbone établis au moyen de méthodes d'ultrafiltration sur un échantillon différent d'os provenant également du Yukon et présentant de semblables fractures et traces d'enlèvements d'éclats. Seulement deux des âges au radiocarbone font partie de la gamme attendue variant entre 25 000 et 40 000 14C ans BP. Six autres âges sont non finis, dont cinq ayant plus de 49 100 14C ans BP. Trois âges finis varient entre 46 500 et 50 500 14C ans BP et ont d'importants écarts-types, et ces âges pourraient également être non finis. Deux hypothèses testables ont été émises afin d'expliquer les structures de fractures observées, la première étant que les fractures ont été causées par des humains et la seconde étant que les fractures sont le résultat d'un processus géologique inconnu à ce jour. Des recherches plus approfondies s'imposent afin de mettre ces deux hypothèses à l'épreuve.

The hectic front of the Denver Museum of Nature & Science hides an unseen back of the museum that is also bustling. Less than 1 percent of the museum's collections are on display at any given time, and the Department of Anthropology alone cares for more than 50,000 objects from every corner of the globe not normally available to the public. This lavishly illustrated book presents and celebrates the Denver Museum of Nature & Science's exceptional anthropology collections for the first time. The book presents 123 full-color images to highlight the museum's cultural treasures. Selected for their individual beauty, historic value, and cultural meaning, these objects connect different places, times, and people. From the mammoth hunters of the Plains to the first American pioneer settlers to the flourishing Hispanic and Asian diasporas in downtown Denver, the Rocky Mountain region has been home to a breathtaking array of cultures. Many objects tell this story of the Rocky Mountains' fascinating and complex past, whereas others serve to bring enigmatic corners of the globe to modern-day Denver. Crossroads of Cultureserves as a behind-the-scenes tour of the museum's anthropology collections. All the royalties from this publication will benefit the collections of the Denver Museum of Nature & Science's Department of Anthropology.

Clovis archaeological sites in the central Great Plains are rare. A surface assemblage of Clovis lithics from the Eckles Site in north central Kansas can therefore make a significant contribution to understanding Clovis lithic procurement, landscape use and mobility. The lithic assemblage is unique in that it contains a discarded tool kit and evidence of a newly produced tool kit both made of White River Group silicate that outcrops about 450 km to the west northwest at Flattop Butte in northeast Colorado. A diverse toolkit indicates that the site was a probable camp site near a kill/processing event. Long distance movement of lithic materials to the east southeast and transport of this material in the form of large bifaces is indicated.

The Angus Mammoth site in south-central Nebraska has been controversial since its discovery in 1931 when a fluted artifact was reported to be associated with the mammoth. For nearly 80 years it has not been known if Angus was a paleontological site predating the human occupation of North America as has been asserted by some geologists and paleontologists, or an archaeological site dating to the late Pleistocene as has been advocated by some archaeologists. Geomorphic study and luminescence dating have finally solved the problem after nearly eight decades. Although microwear and technological analyses have determined that the Angus biface is an authentic artifact, TL and IRSL dates have shown that the matrix above the mammoth is much too old for a mammoth/fluted point association to be valid.

The peopling of the Americas is a topic of ongoing scientific interest and rigorous debate1,2. Holen et al.3 add to these discussions with their recent report of a 130,000-year-old archaeological site in southern California, USA: the Cerutti Mastodon (CM) site, which includes the fragmentary remains of a single mastodon (Mammut americanum), spatially associated stone cobbles, and associated lithic debris that they claim indicates prehistoric hominin activity.

This valuable book is an excellent overview of long-term archaeological investigations in the valley that remains at the forefront of studies on the First Americans.   In southwest Nebraska, a stretch of Medicine Creek approximately 20 kilometers long holds a remarkable concentration of both late Paleoindian and late prehistoric sites. Unlike several nearby similar and parallel streams that drain the divide between the Platte and Republican Rivers, Medicine Creek has undergone 70 years of archaeological excavations that reveal a long occupation by North America's earliest inhabitants.   Donna Roper has collected the written research in this volume that originated in a conference celebrating the 50th anniversary of the 1947 River Basin Survey. In addition to 12 chapters reviewing the long history of archaeological investigations at Medicine Creek, the volume contains recent analyses of and new perspectives on old sites and old data. Two of the sites discussed are considered for pre-Clovis status because they show evidence of human modification of mammoth faunal remains in the late Pleistocene Age. Studies of later occupation of Upper Republican phase sites yield information on the lifeways of Plains village people.   Presented by major investigators at Medicine Creek, the contributions are a balanced blend of the historical research and the current state-of-the-art work and analysis. Roper's comprehensive look at the archaeology, paleontology, and geomorphology at Medicine Creek gives scientists and amateurs a full assessment of a site that has taught us much about the North American continent and its early people.