Contemporaneity of Clactonian and Acheulian Flint Industries at Barnham, Suffolk
Ashton, Nick, McNabb, John, Irving, Brian, Lewis, Simon, Parfitt, Simon, Antiquity
New field evidence challenges an old-established fundamental of the Lower Palaeolithic sequence in Britain.
Excavations at the Lower Palaeolithic site at East Farm, Barnham, Suffolk (Ashton et al. in press) help to change radically the British Lower Palaeolithic sequence. Since the 1930s Barnham has formed a pillar, alongside Swanscombe (Kent), of the traditional framework, with a series of Clactonian flint industries overlain by a single Acheulian industry (Paterson 1937; Roe 1981; Wymer 1985). The two industry types were regarded as chronologically and culturally distinct, the simple core-and-flake Clactonian being replaced by a 'more advanced' industry containing bifaces. Recent work at Boxgrove, Sussex (Roberts 1990) and High Lodge, Suffolk (Ashton et al. 1992) has shown, however, that Acheulian industries also pre-date the Clactonian industries. Other work (McNabb 1992; Ashton & McNabb 1992) indicate a broad variation in British Lower Palaeolithic assemblages, the only real difference between Clactonian and Acheulian being the presence or absence of bifaces. On this basis their cultural distinctiveness has been questioned. Excavations at Barnham during August 1993 have demonstrated that the core-and-flake industry, previously described as Clactonian (Paterson 1937; Wymer 1985), is in fact in the same stratigraphic position as, and contemporary with, biface manufacture.
The site and its palaeoenvironment
At Barnham, Middle Pleistocene deposits survive in the base and around the edges of a disused clay pit. A series of glacial deposits underlie the site, consisting of Lowestoft Till and associated outwash gravels formed during the Anglian glaciation (assigned to Oxygen Isotope Stage 12, c. 450,000 years ago, Bowen et al. 1989). A late glacial/early interglacial channel, up to 7 m in depth, cut into these deposits and was subsequently infilled with sands, silts and clays. The lowest 5 m of these deposits are poorly fossiliferous, but the top 2 m of grey silts and clays have produced abundant faunal remains (Area III).
At the margins of the channel, the grey silts and clays thin and pass laterally into grey silty sands which reach a thickness of less than 30 cm. They cover a single spread of coarse gravels, consisting of medium to large flint cobbles, formed during an earlier stage of the channel's infilling. This 'lag' gravel appears to have been periodically innundated and finally covered by the grey silty sands. Evidence of soil formation has been identified in the dark brown clay unit above the grey silty sands. This unit has possibly been identified at the top of the sequence of silts and clays in the centre of the channel. The whole area was subsequently covered by 'brickearth' composed of brown clays and silts, with further evidence of soil formation at periods during deposition, indicating a complex pedosedimentary history (Kemp in Ashton et al. in press).
Around the margins of the channel the deposits are decalcified, but the upper 2 m of the grey silts and clays in the central part of the channel have yielded a rich fauna (Area III). Changes in the composition of the vertebrate fauna indicate a succession from a fluvial situation to a marsh, as the channel infilled and dried up. Initial colonization of migratory fish, such as salmonids and eel (Anguilla anguilla), gave way to species that prefer slow-moving water, in particular cyprinids and their associated predators, pike (Esox lucius) and perch (Perca fluviatilis). Towards the top of the fossiliferous sequence, the vertebrate fauna is dominated by semi-aquatic species such as frogs, toads, newts and European pond terrapin (Emys obicularis), possibly reflecting the loss of a fluvial link at the site. Pond terrapin, together with common tree frog (Hyla arborea) and Aesculapian snake (Elaphe longissima) indicate a fully interglacial climate with a mean July temperature at least 2-3 [degrees] C higher than present (Holman in Ashton et al. …