Mollusca from Last Interglacial fluvial deposits of the River Thames at Trafalgar Square, London

Abstract

An account is given of the molluscan assemblages recovered from fluvial deposits beneath the ‘Upper Floodplain terrace’ of the River Thames in the vicinity of Trafalgar Square, central London. A total of 37 aquatic and 28 terrestrial taxa have been recorded, a diversity indicative of full interglacial conditions. Palaeobotanical and vertebrate evidence suggests that these fossiliferous sediments belong to the Last (Ipswichian) Interglacial, a conclusion strongly supported by molluscan evidence. The combination of the presence of certain species, such as Belgrandia marginata, Potomida littoralis and Margaritifera auricularia, together with the absence of other taxa that no longer live in Britain, such as Pisidium clessini, Corbicula fluminalis and Unio crassus, imparts a distinctive character to the fauna. These temperate molluscs were not only present in the Trafalgar Square Sands and Silts, but also in the underlying Spring Gardens Gravel, showing the latter to be an interglacial aggradation that did not accumulate during the late Wolstonian, contrary to previous interpretations. Copyright © 1999 John Wiley & Sons, Ltd.