The demise of Neanderthals and their interaction with dispersing anatomically modern human populations remain some of the most contentious issues in palaeoanthropology. The Châtelperronian, now generally recognized as the first genuine Upper Palaeolithic industry in Western Europe and commonly attributed to the Neanderthals, plays a pivotal role in these debates. The Neanderthal authorship of this techno-complex is based on reported associations of Neanderthal skeletal material with Châtelperronian assemblages at only two sites, La Roche-à-Pierrot (Saint-Césaire) and the Grotte du Renne (Arcy-sur-Cure). The reliability of such an association has, however, been the subject of heated controversy. Here we present a detailed taphonomic, spatial and typo-technological reassessment of the level (EJOP sup) containing the Neanderthal skeletal material at Saint-Césaire. Our assessment of a new larger sample of lithic artifacts, combined with a systematic refitting program and spatial projections of diagnostic artifacts, produced no reliable evidence for a Neanderthal-Châtelperronian association at the site. These results significantly impact current models concerning the Middle-to-Upper Palaeolithic transition in Western Europe and force a critical reappraisal of who exactly were the makers of the Châtelperronian.

Chert alteration in Paleolithic contexts, generally known as "patina" by prehistorians, has long been recognized. Originally, different types of "patina" were defined as "white patina", "glossy patina", or "porcelain-like patina", all of which involved changes in the color and/or roughness of the initial raw material. Alteration degrees are used in many research fields like taphonomy, petroarchaeology or usewear analysis; however most of these studies are still based on qualitative descriptions using a wide range of terms that bring about confusion. In this paper, we present first the results of an inter-observer's blind-test where color and roughness are described at macroscopic scale. Secondly, we use quantitative methods to compare archaeological and experimental altered silicifications: light spectrometry and confocal microscopy are used to quantify color and roughness. We show here how macroscopic qualitative descriptions could lead to confusion because of the lack of calibration and the number of terms used differently by each one. We demonstrated the efficiency of quantitative methods as light spectrometry and confocal microscopy that will significantly enhance studies of surface alteration in terms of taphonomy, use-wear analyses, and petroarchaeology issues as well as interdisciplinary discussions.

Post-depositional modifications or alterations of the surface of lithics artefacts have been characterised at both macroscopic and microscopic scales by means of qualitative criteria. Here we introduce a new methodology for the study of surface alterations based on roughness measurements using confocal microscopy. This new approach allows for a quantified and reproducible distinction between various states of alteration among geological samples and archaeological material from a level attributed to the Châtelperronian at La Roche-à-Pierrot (Saint-Césaire, France). This site, perhaps best known for discovery of Neanderthal remains in a level attributed to the Châtelperronian, plays a critical role in questions concerning the emergence of the Upper Palaeolithic and its relation to the appearance of anatomically modern humans in Western Europe. In this context, the question of the chrono-cultural integrity of the Châtelperronian at Saint-Césaire is crucial. Our results demonstrate considerable variability in surface alterations among a sample of specific artefacts, Châtelperronian points, and those collected in the immediate vicinity of the Neanderthal remains and thus reinforces previous arguments concerning the unreliability of the Neanderthal-Châtelperronian association at Saint-Césaire. This pilot study equally confirms the potential of roughness analysis for both taphonomic and use-wear studies of lithic industries.