Fleeting finds: Investigating intertidal discoveries in the Severn Estuary

This article is from Current Archaeology issue 418

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Archaeological sites exposed in intertidal zones can be exceptionally rich in terms of their preservation of organic finds and environmental evidence. Such discoveries often follow storms, which erode sediments to expose underlying remains – but these may only be exposed for a few hours at low spring tides before they are covered again by mobile mud and sand, perhaps never to be seen again, or to re-emerge in changed form a decade later. Building up the full story of a site can therefore require decades of observations, as well as funding from multiple sources, and an interdisciplinary team of researchers – as the history of research over the last 33 years at Goldcliff in the Severn Estuary shows.

This work began in 1991, when a storm sparked the excavation of an Iron Age site located between the Prince of Wales Bridge (Second Severn Crossing) and Newport. Preserved within the estuary’s intertidal peats were the remains of eight rectangular Iron Age buildings and a series of trackways, and surviving environmental evidence revealed that these related to spring and summer grazing of cattle on the saltmarsh. They were not the only archaeological remains to emerge from this area, however: between 1991 and 1993 surveys (funded by Cadw) uncovered a Mesolithic site, two planks from a Bronze Age sewn-plank boat, and human skulls that had been deposited at the edge of a former bedrock island surrounded by wetland during the Bronze Age. Following these initial explorations, Dr Heike Neumann undertook a wider survey (funded by the Board of Celtic Studies) of the entire intertidal zone between Cardiff and the bridge, revealing a wealth of other sites – particularly those of Bronze Age date – some of which, including Redwick and Peterstone, would go on to be excavated. The headland at Goldcliff, the remains of a former island, would also prove to contain many more secrets than we first suspected.

As part of our early fieldwork, in 1993 we had identified the extensive remains of a submerged forest to the east of the former island – but, as it produced little other archaeological evidence, it was rather dismissed at the time. Fast forward to 2001, though, and our Reading University team succeeded in getting funding from the Natural Environment Research Council (NERC) for a project studying Mesolithic to Neolithic Coastal Environmental Change. One of the submerged forests we decided to focus on was the apparently archaeologically unpromising area east of the island. We were lucky with our timing, as the Severn foreshore was relatively clear of mud and sand, and within a day of starting work we discovered human, animal, and bird footprints preserved in a 6m sequence of laminated silts which had accumulated as a result of sea-level rises, separating two Mesolithic submerged forest layers. The discovery of footprints was not unprecedented: the late Professor John Allen, who was a member of our project, had recorded footprints on several other sites in the estuary, and had collaborated with the late Professor Stephen Aldhouse-Green and others on the investigation of Mesolithic footprints identified 4km to the west at Uskmouth. The Goldcliff examples would add exciting new information to this growing picture.

Recreating landscapes

At Goldcliff, we selected an area of the submerged forest to make a detailed plan, where each tree would be identified and linked to analysis of pollen and insects to help investigate woodland composition and history. In one small corner of this area, the old land-surface below the forest peat was exposed, and as we cleaned this for recording, charcoal and flint artefacts emerged. This was dubbed Mesolithic occupation Site J, and as we redoubled our attention east of the island we discovered two further Mesolithic occupation sites: one within the Lower Submerged Forest (Site B), and one lying between the two forest layers (Site A).

The earliest Mesolithic evidence was associated with the Lower Submerged Forest, which dates to c.5800 BC and pre-dates the later inundation of this woodland. The latest Mesolithic occupation, Site J, lies beneath the Upper Submerged Forest layer and dates to c.4800 BC. Our excavations, undertaken in parallel with the NERC project and part-funded by Cadw in 2002-2003, revealed concentrations of worked stone, but not in great density, perhaps suggesting areas of short-term activity. Mesolithic groups were also using this landscape for hunting; surviving animal bone suggests that their prey included red deer, roe deer, boar, and aurochs, as well as otter and wolf, and some birds. There was evidence of fish, too, particularly eels. Excitingly, the peat had also preserved wooden artefacts at Site J: a pointed stick and a carved Y-shaped object. Wooden artefacts are very rare on Mesolithic British sites – and equally rare and exciting is the association between these excavated settlement sites and the footprint evidence.