PALEONTOLOGY AND TAPHONOMY OF LATE QUATERNARY FOSSIL ASSEMBLAGES AT SOMERSHAM, CAMBRIDGESHIRE, ENGLAND, AND THE PROBLEM OF REWORKING

Assemblages of foraminifers, ostracods and molluscs from temperate Ips wichian Stage (last temperate stage) sediments and overlying cold Deve nsian Stage (last cold stage) sediments at Somersham in the southern F enland of Cambridgeshire have been analysed. The Ipswichian sediments contain faunas consistent with temperate brackish water conditions und er tidal influence. The Devensian assemblages were recovered from a se ries of sands and gravels laterally accreting in a channel cutting int o Ipswichian sediments. In contrast to the Ipswichian faunas, the faun as of particular Devensian samples show a complex mixture of temperate freshwater, brackish and marine taxa. The molluscs are mainly freshwa ter, with few land snails; they occur together with foraminifers and o stracods. Freshwater, brackish water and marine ostracods are present with foraminifers. A sample of Devensian fine laminated sediment in th e channel was analysed for pollen; only abundant pre-Quaternary spores were present, with abundant foraminifers in the same sample. The taph onomy of the assemblages and the difficulties of their interpretation in environmental terms are discussed. The importance of taphonomy in a ssessing environments, climate, range of taxa and dating is stressed.