Between flint and mammal bone refits: A double spatial Mikado game at Cagny-l’Épinette (Levels I to J, fluvial sequence)

• Spatial analysis of Acheulean assemblages in an alluvial context at Cagny-l’Épinette. • Contribution of faunal and lithic refits to an archaeostratigraphic and taphonomic study. • Identification of a single archaeostratigraphic level within the fluvial sequence. • Results confirm a primary deposit context with minor horizontal reworking. • Results highlight syn- or post-burial vertical movements. It is acknowledged that bone and lithic refits constitute suitable complementary tools to address site archaeostratigraphy and site formation processes. However, there are few sites – especially Lower Palaeolithic ones – where both lithic artefacts and faunal remains have been refitted, making detailed combined spatial analyses of the two even rarer. Therefore, possessing both flint and bone refits, the Acheulean open-air site of Cagny-l’Épinette (Somme Valley, France) has provided a rare opportunity for their simultaneous spatial analysis. The refits were included in the first site-wide analysis of the assemblages embedded in fluvial deposits (MIS 9), rich in thousands of flint artefacts and faunal remains. This analysis mobilized multidisciplinary, multi-decade data. Several criteria were thus assessed for both lithic artefacts and faunal remains, as individuals and as part of refittings: size class, orientation, natural surface modifications, anthropogenic marks and skeletal part representation. Our analysis has brought new conclusions to the decades-long debate on the archaeostratigraphic division of the Acheulean assemblages and their taphonomic status. This paper presents the contribution of refits that helped to demonstrate the presence of a single, primary context archaeostratigraphic level. We discuss how, when combined with multidisciplinary data, refits have proved to be a determining tool for identifying the different agents, natural and anthropogenic, involved in the site formation and in assessing their role in any movements. Our research highlights the informative potential of refits, essential in any Pleistocene site formation analysis, thus encouraging us to engage more in the, unfortunately time-consuming, task of refitting.