Molluscan evidence for differentiation of interglacials within the 'Cromerian Complex'

Usage of the term 'Cromerian' differs between countries. In the Netherlands , four interglacial stages (and associated cold stages) are included within the so-called 'Cromerian Complex'. In Britain, where the Cromerian stratot ype is located, all 'Cromerian, sites have, until fairly recently, been att ributed to different parts of a single interglacial stage. The first sugges tion that this view might over-simplify reality was based on vertebrate evi dence, in particular the occurrence of Arvicola terrestris cantiana, rather than Mimomys savini., in some deposits. Molluscan assemblages also exhibit significant differences between sites that have been attributed to the sam e interglacial stage. Valvata goldfussiana appears to characterize fluvial assemblages in the early part of the Cromerian Complex, whereas Valvata nat icina typifies several of those that occur later. Combining molluscan and v ertebrate evidence, it seems likely that as many as five distinct stages ha ve been conflated and that the stratotype at West Runton occurs early in th e Cromerian Complex, rather than immediately preceding the Anglian Stage. ( C) 2001 Elsevier Science Ltd. All rights reserved.