Barnfield Pit is the best known of a number of pits in the Swanscombe area that were quarried for gravel and underlying Chalk. The sequence and associated archaeology have been known since the early 20th century (Smith & Dewey, 1913; Ovey 1964; Bridgland 1994; Conway et al. 1996). There have been two major excavations at the site, those by the Wymers in the 1950s and by Waechter from 1968-72. The Thames terrace deposits, which rest on Chalk and London Clay, consist of the Lower Gravel, Lower Loam (Stage I), Lower Middle Gravel and Upper Middle Gravel (Stage II), and a series of overlying sands, loams and gravels (Stage III). The fluvial sediments (Stages I and II) are attributed to MIS 11 on the basis of stratigraphy (Bridgland, 1994), amino acid ratios (Penkman et al. 2011) and biostratigraphy (Schreve 2001; Ashton et al. 2008). Changes in the molluscan assemblages enable correlation with other sites and with the Hoxnian pollen record. This suggests that the Lower Loam can be attributed to HoII and the Middle Gravels to HoIII (Kerney 1971; Preece et al. 2007).

There are artefact assemblages from all the Stage I and Stage II deposits. Those from the Lower Gravels and Lower Loam consist of cores, flakes and flake tools, including an in situ refitting assemblage from within the Lower Loam called ‘the knapping floor’. These assemblages lack handaxes and have been described as ‘Clactonian’. The assemblages from the Middle Gravels are quite different in character and include a large number of pointed handaxes attributed to the Acheulian. From the Upper Loam in the Stage III sequence there are small collections of ovate handaxes. The age of the Upper Loam is unknown.

The differences in the assemblages from Stage I and II deposits is the main support for a cultural interpretation for the Clactonian and the Acheulian, being distinct populations with different knapping repertoires and skills. There has been recent support for this interpretation from the excavation of the nearby elephant butchery site at Southfleet Road, Ebbsfleet (Wenban-Smith 2013). The site is associated with a non-handaxe assemblage, which is probably equivalent in age to the Lower Loam and sits beneath the Middle Gravels.

The humans responsible for the Middle Gravel assemblages is known from the Swanscombe skull. In 1935 and 1936 the occipital and left parietal bones from a human skull were discovered by Alvin Marston, a dentist. Remarkably the right parietal of the same skull was excavated by John Wymer and his father in 1955.

Related nearby sites include Baker's Hole and Southfleet Road

Human fossils

The huge number of fossils retrieved from the gravels around Swanscombe includes those of one early human individual. In 1935 Alvin Marston was collecting stone tools and fossils from Barnfield Pit when he recognised a human occipital bone. Over the next nine months he visited the site and continued his search. In March 1936 he was rewarded with a left parietal bone. Some 20 years later Bert Wymer and his son John located and then began excavation in a remaining patch of the gravels from which Marston had retrieved these fossils. Soon afterwards the right human parietal bone of the same individual was unearthed. These three pieces of a ~400,000-year-old skull, found scattered in the gravels of Barnfield Pit over the course of 20 years and during two separate searches, fit together perfectly. Due to the slight muscle markings it is thought that they belonged to a young woman. Endocranial examination suggests her brain was comparable to ours in size, and also in its external structure and convolutions.

In overall shape the occipital and parietal bones resemble those from a skull of broadly similar age from Steinheim in Germany, as well as those of early members of the Neanderthal lineage from Ehringsdorf and Reilingen (Germany), Biache (France) and the Sima de los Huesos (Atapuerca, Spain). The presence of one small feature seems to corroborate these similarities in shape – a suprainiac fossa, a small depression in the middle of the occipital bone that is very rare in recent humans, can be found on these other skulls, as well as in all known Neanderthals.

Archaeological Tabulation

Excavated assemblages from Waechter excavations 1968-72 (Conway et al. 1996) and from Wymer excavations 1955-60 (Ovey 1964).

LG = Lower Gravel; LL = Lower Loam; LL KnF = Lower Loam knapping floor; LMG = Lower Middle Gravel; UMG = Upper Middle Gravel.