Timeline: prehistoric occupation and burnt mound activity in Pembrokeshire

Recording along the South Wales natural gas pipeline, detailed in CA’s latest Monograph, Timeline, revealed many significant remains, including a Neolithic henge, but there were many more features that, although less spectacular, collectively transform our understanding of early occupation in South Wales. At Upper Neeston, Pembrokeshire, the archaeological remains fell into both categories.

The early prehistoric cove feature
The early prehistoric cove feature

These discoveries were made possible by the vigilance of the watching brief team who were monitoring the crossing of a small stream. Here, they spotted part of a wooden object just below the marshy surface. Given its shallow depth, the object was initially presumed to be of relatively recent date, but a priority radiocarbon date and further excavation demonstrated that it was in fact a trough belonging to the Middle Bronze Age. A decision to extend the excavation was taken and further remains were revealed.

The earliest of these included an enigmatic cove feature and many pits, dating from the Early Neolithic through to the Early Bronze Age. Such pits, typically small and unspectacular, were found with unexpected regularity along much of the western section of the pipeline. An intensive programme of radiocarbon dating, one of the largest ever undertaken in Wales, has made it possible to demonstrate the density of human occupation along the route during those millennia, revealing that early prehistoric South Wales was at times well settled, but with distinct pulses of activity.

A Middle Bronze Age burnt mound: the wooden trough and hearth are visible in the centre of the photograph
A Middle Bronze Age burnt mound: the wooden trough and hearth are visible in the centre of the photograph
First minister Rhodri Morgan (second from left) and the Bronze Age trough
First minister Rhodri Morgan (second from left) and the Bronze Age trough

Some 2000 years after Neolithic occupation began on the site, a stream became a focus of activity, where hot stones were used to generate steam or hot water, which resulted in the formation of a burnt mound. Water contained in the wooden trough was heated by stones placed in an adjoining hearth. While this process is well understood, the purpose of such features remains a matter of ongoing debate, with use for cooking, craft activities, brewing and saunas all suggested. Over 40 such mounds were found along the pipeline, with radiocarbon dating at one site indicating reuse over a remarkably long timespan of over 1500 years.

The findings generated much interest, including a visit from the then First Minister for Wales, Rhodri Morgan.

The same site was later used for Roman food production, with small paddocks and crop-processing ovens reflecting intensified agricultural production following the conquest of Wales (c. AD 47–78), something evidenced at several other sites along the route.

Jon Hart

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