New faunal analyses and amino acid dating of the Lower Palaeolithic site at East Farm, Barnham, Suffolk

Rich assemblages of non-marine molluscs are described from the Lower Palaeolithic site at East Farm, Barnham, Suffolk. The assemblages from the upper levels of a channel infill (Unit 5c) reflect both aquatic and terrestrial habitats and indicate temperate conditions throughout the fossiliferous sequence. The land snail fauna contains Discus ruderatus, which allows correlation with the lower part of the molluscan succession at the nearby Lower Palaeolithic site at Beeches Pit, West Stow. Palaeontological evidence from both sites suggests attribution to the Hoxnian Stage, broadly equivalent to part of MarineOxygen Isotope Stage (MIS) 11. A tooth of pipistrelle bat (Pipistrellus pipestrellus) from the same deposits represents its only known occurrence from the British Hoxnian. The molluscan assemblages from certain levels at Barnham had clearly suffered considerable post-mortem sorting and diagenesis. Not only were there huge differences in the representation of Bithynia shells and their opercula but the apertures of some shells showed evidence of significant recrystallization. Moreover, some of the opercula were slightly folded or even crumpled, indicating that they must once have been soft and deformable rather than hard and brittle. Such diagenetic, effects are likely to have compromised their suitability for amino acid dating. New amino acid analyses were therefore undertaken of the intra-crystalline component of both pristine and distorted opercula. The results indicated that, of 12 opercula analysed, only one showed any serious anomaly, underlining the importance of careful sample selection. The new data from these calcitic opercula support earlier conclusions, based on D-alloisoleucine/L-isoleucine ratios from aragonitic shells, that the fossiliferous sediments at Barnham accumulated during MIS 11.