jats:titleABSTRACT</jats:title>jats:pThe buried soil above the Goodwood‐Slindon Raised Beach running along the foot of the South Downs (Sussex) is one of the most extensive Lower Palaeolithic land surfaces known. It extends for 16 km but exposures are limited to Boxgrove, the focus of archaeological excavations since the 1980s, and Valdoe, 4.8 km to the west. The palaeosol yielded vertebrates suggesting attribution to Marine Isotope Stage (MIS) 13 and land snails important in the reconstruction of local environments. Important differences exist between the molluscan assemblages from Valdoe and Boxgrove. An extinct land snail jats:italicRetinella</jats:italic> (jats:italicLyrodiscus</jats:italic>) jats:italicelephantium</jats:italic>, previously known in Britain only from MIS 11, occurred at Valdoe at unusually high frequencies in assemblages poor in woodland species, prompting a reappraisal of its stratigraphical and ecological significance. Conversely, jats:italicSpermodea lamellata</jats:italic>, a woodland species present at Boxgrove, was absent at Valdoe. This lateral variability results both from the original heterogeneity of the environment, and from differential preservation resulting from decalcification and erosion. Calcitic slug plates are over‐represented (>50% of the molluscan fauna) in decalcified sediments where shells composed of aragonite are rare. These considerations, and comparisons with modern and fossil assemblages, have led to more nuanced reconstructions of the landscape occupied by early humans in southern England ~500 ka ago.</jats:p>