The Plainview/Folsom-aged bison Bonebed 2 at Bonfire Shelter, originally excavated in the 1960s, is argued to be the earliest North American bison jump (Dibble 1970; Dibble and Lorrain 1968). Yet, it is far older than all other known jumps, and well south of where the great majority of these sites are found. Dibble (1970) reasonably argued that its age and location was not compelling evidence against it being a bison jump. However, Binford (1978) observed that the skeletal composition of Bonebed 2 did not resemble a kill. To assess whether Bonfire Shelter could have been utilized as a jump and whether it was, we explore two lines of evidence bearing on the issue, a GIS analysis of the site and upland topography, and zooarchaeological analysis of the recovered bison remains. Although our GIS analysis indicates that Bonfire Shelter meets many of the criteria of a jump locality, our reanalysis of the faunal remains suggests this was not the primary kill locus, but instead a processing area to which high-utility portions of at least 24 bison were transported and butchered. Where the bison were killed, and how, is not known.

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The invention and proliferation of stone tool technology in the Early Stone Age (ESA) marks a watershed in human evolution. Patterns of lithic procurement, manufacture, use, and discard have much to tell us about ESA hominin cognition and land use. However, these issues cannot be fully explored outside the context of the physical attributes and spatio-temporal availability of the lithic raw materials themselves. The Olduvai Basin of northern Tanzania, which is home to both a wide variety of potential toolstones and a rich collection of ESA archaeological sites, provides an excellent opportunity to investigate the relationship between lithic technology and raw material characteristics. Here, we examine two attributes of the basin's igneous and metamorphic rocks: spatial location and fracture predictability. A total of 244 geological specimens were analyzed with non-destructive portable XRF (pXRF) to determine the geochemical distinctiveness of five primary and secondary sources, while 110 geological specimens were subjected to Schmidt rebound hardness tests to measure fracture predictability. Element concentrations derived via pXRF show significant differences between sources, and multivariate predictive models classify geological specimens with 75-80% accuracy. The predictive models identify Naibor Soit as the most likely source for a small sample of three lithic artifacts from Bed II, which supports the idea that this inselberg served as a source of toolstone during the early Pleistocene. Clear patterns in fracture predictability exist within and between both sources and rock types. Fine-grained volcanics show high rebound values (associated with high fracture predictability), while finer-grained metamorphics and coarse-grained gneisses show intermediate and low rebound values, respectively. Artifact data from Bed I and II suggest that fracture predictability played a role in raw material selection at some sites, but other attributes like durability, expediency, and nodule size and shape were more significant.

In Byerly et al. (2005) we explored the hypothesis that the Paleoindian component at Bonfire Shelter was the result of a jump kill. Our efforts involved extensive mapping and GIS analysis, a re-examination of the Paleoindian-age bison assemblage, and consideration of the geomorphic history of the canyon in which the site is located. We concluded that the preponderance of evidence indicated the Paleoindian-age bison remains at Bonfire Shelter marked a processing site as Binford (1978) suggested, rather than a primary kill locality as originally interpreted (Dibble 1968). Bement (this issue) raises several concerns about our analysis and discussion, including that we omit pertinent information relevant to the interpretation of the site. His comments, however, result from a misreading of our discussion and a misconstrual of the data set, as we explain in this response.

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