opposite Works to install a 317km gas pipeline in south Wales have offered archaeologists the opportunity to carry out one of the longest excavations in Wales one of their most significant discoveries was a previously unknown Neolithic henge at Vaynor Farm in Carmarthenshire. Its remains can be seen in the foreground, while the pipeline corridor stretches away into the distance.

Carmarthenshire’s missing monument: how one of the biggest excavations in Wales uncovered a long-lost henge

The installation of the South Wales Gas Pipeline allowed archaeologists to investigate a 317km corridor stretching from the Pembrokeshire Coast to Gloucestershire. Their finds have illuminated more than 10,000 years of human history, including the previously unknown remains of Britain’s most south-westerly Neolithic henge. Current Archaeology's Carly Hilts reports.

Start

Over 4,500 years ago, a Neolithic community in what today is Carmarthenshire came together for an ambitious building project. Probably armed with stone and antler tools, they cut deep ditches into the underlying bedrock and heaped earth on either side to create imposing banks. The effort and numbers required to complete this construction must have been considerable, but the group were motivated by a literally monumental aim. The resulting henge seems to have been a focus for ceremonial activities that would have been of great importance to the local population. Yet, over time, the site fell both out of use and memory, only to be rediscovered millennia later during one of the longest excavations ever carried out in Wales.

opposite Works to install a 317km gas pipeline in south Wales have offered archaeologists the opportunity to carry out one of the longest excavations in Wales one of their most significant discoveries was a previously unknown Neolithic henge at Vaynor Farm in Carmarthenshire. Its remains can be seen in the foreground, while the pipeline corridor stretches away into the distance.
Works to install a 317km gas pipeline in south Wales have offered archaeologists the opportunity to carry out one of the longest excavations in Wales one of their most significant discoveries was a previously unknown Neolithic henge at Vaynor Farm in Carmarthenshire. Its remains can be seen in the foreground, while the pipeline corridor stretches away into the distance.

It is not often that we are able to explore an area’s archaeology on a landscape scale, but major infrastructure projects offer just such an opportunity, opening corridors through vast areas and enabling archaeologists to compare finds across a much wider context than is usually possible. One such initiative was the South Wales Gas Pipeline, which saw construction – and attendant archaeological investigations – along a 317km route stretching from the coastal plains around Milford Haven, via the uplands of the Brecon Beacons National Park and through Herefordshire, terminating at Tirley in Gloucestershire. The work was undertaken between 2005 and 2007, and saw the involvement of numerous archaeological organisations, including Cotswold Archaeology, Network Archaeology, Cambrian Archaeological Projects, the Welsh Archaeological Trusts, Groundworks Archaeology, and the Rhead Group.

Together, their endeavours have revealed a vivid slice of human life spanning more than 10,000 years, from the Mesolithic period to the dawn of industrialisation. Post-excavation analysis – funded by National Grid – is now complete, and Cotswold Archaeology has published a comprehensive synthesis of the archaeological findings, Timeline: the archaeology of the South Wales Gas Pipeline (see ‘Further reading’ on p.32; the broader data sets resulting from this research can be accessed at https://reports.cotswoldarchaeology.co.uk). The diverse discoveries described in its pages help to illuminate how human activities have varied within a wide area and over a long span of time. These range from clusters of enigmatic Neolithic and early Bronze Age ‘burnt mounds’ in Pembrokeshire and archaeological echoes of the post-medieval charcoal industry in Canaston Woods, to intriguing individual finds such as a well-preserved copper halberd blade with traces of its wooden haft still surviving, which was unearthed during the excavation of a Beaker-period ring ditch at Trecastle, Powys.

One of the most significant discoveries, however, was a previously unknown henge that was identified at Vaynor Farm in Carmarthenshire. Described in a chapter by Timothy Darvill, Professor of Archaeology at Bournemouth University, the monument had commanded a lofty position on open high ground with sweeping views over the River Taf and surrounding wooded valleys. It is the most south-westerly henge yet discovered in Britain, adding important new information to our understanding of Neolithic ceremonial sites across the UK – however, due to centuries of agricultural activity on the site, today nothing of the monument survives above ground. Instead, it was initially identified during pre-construction geophysical survey, which revealed the clear outline of its ditches to hint at the henge’s scope.

Above The South Wales Gas Pipeline crossed the boundaries of archaeological trusts, and investigations involved many organisations. The white numbers represent some of the sites discussed in Timeline; 503 is Vaynor Farm, while 38.17 is where the Trecastle halberd was found.
The South Wales Gas Pipeline crossed the boundaries of archaeological trusts, and investigations involved many organisations. The white numbers represent some of the sites discussed in Timeline; 503 is Vaynor Farm, while 38.17 is where the Trecastle halberd was found.

Monumental remains

Two curved ditches (Darvill describes them as ‘banana-shaped’) testify to a moderately sized monument, demarking an oval enclosure with an interior space of 18.5m by 13.5m – though it may have been as much as 3m wider originally, as erosion has broadened the ditches, eating into the inside of the henge. The ditches themselves were deeply cut, steep-sided, and flat at the base – areas of scorched earth on their floor bear witness to the effort of creating these rock-cut curves, possibly representing fires lit to help break up the ground during their construction. They are thought to have been around 5m wide (eroded to around 8m in places) and 1.9-2.5m deep, dipping further at their northern terminals to a depth of 3.3m; combined with outer banks some 5m wide and up to 3m high, these earthworks would have formed an impressive and very visible monument crowning the high ground.

Two opposed entrances, each around 4m wide, allowed access to the henge, and their locations shed further light on how the site may have been used. The gaps form a clear axis running through the length of the monument, which aligns with the sunrise at the Midsummer Solstice, and sunset at the Midwinter Solstice. Perhaps it was these dates in particular that drew people to the site to carry out communal rites. As for what took place inside the henge, 12 pits or sockets form an oval that would have originally stood around 1m from the inner edge of the ditches (prior to erosion), precisely following their lines and respecting the two entrances. These were substantial, steep holes, 0.9-1.2m across and 0.6-1.2m deep, and the presence of packing stones in some of them suggests that they may have once supported an arrangement of tall timber posts or standing stones. There was no sign of any other contemporary structures or features within the henge, although as the Neolithic ground surface has been ploughed away it is possible that other traces have been lost – and, with them, further clues to the activities that this site had witnessed.

Deliberate destruction?

If the henge had been host to religious gatherings, however, it seems to have been venerated only for a relatively short period of time, with its ditches soon left to erode and silt up, or possibly even deliberately filled in. Layers of soil within the ditches, combined with extensive radiocarbon dating, speak of a long and complex history of construction, use, erosion, and perhaps deliberate destruction. From this analysis, we know that the earthworks are late Neolithic in origin, with their construction beginning before 2600 BC and reaching completion by c.2490-2290 BC. The oval stone- or post-setting was added between c.2640 and c.2350 BC, but within as little as a century it had been dismantled again, going out of use by c.2470-2120 BC.

left Archaeologists working on the route of the pipeline were faced with a diverse range of environments, from rolling terrain on the Milford Haven Aberdulais section (above) to digging remote test pits on Mynydd Myddfai (below).
Archaeologists working on the route of the pipeline were faced with a diverse range of environments, from rolling terrain on the Milford Haven Aberdulais section (above) to digging remote test pits on Mynydd Myddfai (below).

No artefacts have been found to hint at what was going on during the period when the monument was in use, but charcoal recovered from the lower levels of the ditch speak of hazel, oak, and hawthorn from the local landscape being burnt – ‘presumably for offerings or feasts associated with ceremonies undertaken at the henge,’ Darvill suggests. Subsequent ditch fills paint a very different picture of how the site later came to be treated, though: they speak of the henge banks being levelled and their material being cast into the ditches in what may have been a deliberate slighting of the monument. Radiocarbon dating and the presence of sherds of coarse Beaker pottery suggest that this dramatic demolition took place in the early Bronze Age – thought to be a period of significant social, political, and cultural change, as large numbers of ‘Beaker people’ migrating from the Continent brought with them new technology and ideas (as well as significant genetic turnover – see CA 338). These new concepts are thought to have included religious practices and the burial of single inhumations. However, the old tradition of cremating the dead and burying their burnt remains in cemeteries re-emerged around 2100 BC. Two such burial grounds have been identified in the immediate vicinity of Vaynor Farm: one lying 200m to the west, which was also discovered during the pipeline project, and one 350m to the north, unearthed during road improvement works.

right The henge site in its wider landscape. During the Neolithic period, it had occupied largely open, grazed land on a ridge overlooking the River Taf, surrounded by wooded valleys.
The henge site in its wider landscape. During the Neolithic period, it had occupied largely open, grazed land on a ridge overlooking the River Taf, surrounded by wooded valleys.

Could it be that henges like that at Vaynor Farm were thought to be out of step with the new thinking of the early Beaker or Chalcolithic world, and that the site had been deliberately decommissioned – whether it had been violently destroyed as an unwelcome reminder of the ‘old ways’ or carefully buried as a respected but redundant space? If this was the case, it is not the only Neolithic monument to show such signs: recent research focusing on Mount Pleasant, a ‘mega-henge’ in Dorset, suggests that some of its key features had also been deconstructed during the Beaker period (see CA 371).

Vaynor Farm’s henge was not completely erased, however: its infilled outline survived as very slight earthworks that remained visible at least until the Roman period – at which point it seems to have attracted further attention, and perhaps saw ritual activities returning to the site more than 2,000 years after it was first built.

Roman rituals

These later visitors left traces in the form of small quantities of early Roman pottery, including parts of a 2nd-century jar or bowl made of Dorset Black Burnished ware, as well as sherds from a Baetican amphora that was used to import olive oil from southern Spain in the 1st-3rd centuries. They were recovered from the upper ditch fills, together with fragments of burnt bone and stone. What were these people doing? Fortuitously, unlike their Neolithic predecessors, evidence of internal features associated with this group had survived in the form of two four-post structures and two small pits. Within the pits lay the burnt remains of up to two sheep or goats and a lamb or kid, as well as other fragments of charred animal bone, some of which preserved butchery marks. Radiocarbon analysis of charcoal and burnt cereal grains recovered from the pits confirms that these animals were also linked to early Roman activities, yielding dates of AD 70-250, AD 60-230, and AD 120-330.

left Overlooking the remains of the henge, along the axis of its two entrances which were aligned on sunrise and sunset at the two solstices. Its curved rock-cut ditches would once have been flanked by imposing ditches, and post- or stone-holes visible within the ditches (prior to erosion they would have been located around 1m from their inner edge) may have supported an arrangement of timber or stone uprights.
Overlooking the remains of the henge, along the axis of its two entrances which were aligned on sunrise and sunset at the two solstices. Its curved rock-cut ditches would once have been flanked by imposing ditches, and post- or stone-holes visible within the ditches (prior to erosion they would have been located around 1m from their inner edge) may have supported an arrangement of timber or stone uprights.

What was the significance of the four-post structures? On settlement sites, constructions like these are sometimes interpreted as granaries that had been raised off the floor to protect their contents. The Vaynor Farm footprints were not found near any obvious domestic remains, however, and their location within a ceremonial monument like a henge might suggest that they too could have had a ritual role. Might these have been platforms associated with pyres used for animal sacrifice, something that could also be reflected in the presence of burnt animal bones? If so, perhaps we might imagine local populations returning to the enigmatic earthworks, perhaps at a time when the community was under some kind of stress, to carry out their own votive traditions in a previously significant space.

above Two Bronze Age cemeteries have been discovered in the immediate vicinity of Vaynor Farm: one found during road improvement works on the A477, and the other (Site 222) during the pipeline works. Burial traditions bear witness to dramatic changes in religious practices in prehistoric Britain; might these new ideas have also heralded the demise of the henge?
Two Bronze Age cemeteries have been discovered in the immediate vicinity of Vaynor Farm: one found during road improvement works on the A477, and the other (Site 222) during the pipeline works. Burial traditions bear witness to dramatic changes in religious practices in prehistoric Britain; might these new ideas have also heralded the demise of the henge?

This renewed interest was not to endure, however: we know that the henge remains were still visible into the medieval period, as pottery evidence testifies to continued visits, but after this the site seems to have faded from the landscape, and from local memory. It is not featured on any historic maps of the area, and appears to have been completely lost until the South Wales Gas Pipeline excavation brought it to light once more.

Further reading
Timothy Darvill, Andrew David, Seren Griffiths, Jonathan Hart, Heather James, and James Rackham, Timeline – the Archaeology of the South Wales Gas Pipeline: excavations between Milford Haven, Pembrokeshire and Tirley, Gloucestershire, Cotswold Archaeology Monograph 13, £20, ISBN 978-0993454578, available from www.oxbowbooks.com.

All images: Cotswold Archaeology.