Evidence for tanning from plant and insect remains

[FIRST PARAGRAPH] It is suggested elsewhere (Hall and Kenward forthcoming) that a bioarchaeological 'indicator group' (sensa Kenward and Hall 1997) for tanning may be recognisable. The material giving rise to this hypothesis was discovered during assessment of samples from Anglo-Scandinavian and early post- Conquest riverside deposits at Layerthorpe Bridge, York (Carrott et al. 1997). Here, large quantities of bark fragments (and the sclereids -small clumps of lignified cells characteristic of certain trees, notably oak- left when bark decays) were recorded in many samples. These gave the suspicion that the bark was being employed for some purpose, since there was usually very little wood present with it. Much the most likely process to have required bark in bulk is tanning (taken here to represent the steeping of hides in pits or vats with tree bark). Support for this came from a somewhat surprising direction. The beetle Trox scaber was unusually abundant (it was found in 30 of the samples, at a frequency of 3-6 per sample when present; five samples contained 'several' individuals and one 'many’, on the semi-quantitative scale used for recording). This contrasts with the evidence from Anglo-Scandinavian Coppergate, where it was present in a large proportion (242) of the samples but was never abundant. There were only eight cases where three or four individuals were noted, the rest being ones or twos, and the mean number of individuals per sample where the beetle was present was 1.2 (AY 14/7; Kenward, unpublished database). Thus T. scaber was significantly more abundant at the Layerthorpe Bridge site than at Coppergate.