Late Bronze Age enclosure identified on Cothelstone Hill

Published by Dan Broadbent on

We have now received carbon-14 dates from charcoal samples recovered from our excavations on Cothelstone Hill in the summer of 2021. Coupled with interpretation of the results of a LiDAR survey commissioned of the entire QLPS area, the carbon dates indicate the presence of a previously unknown Late Bronze Age enclosure on the top of Cothelstone Hill, transforming our understanding of the prehistory of the hill.

In June 2021, on the day that lockdown restrictions were lifted in England, our programme of archaeological works kicked off in earnest with a two-week community excavation on the top of Cothelstone Hill. Thirty volunteers from the local community, along with a small team of experienced amateurs, joined professional archaeologists from the South West Heritage Trust and QLPS to investigate what was previously believed to be a linear ‘cross-ridge dyke’ of a likely Iron Age date. On the ground, the remains of this feature appeared as an earthwork bank, 2.5m wide and 1.4m high, extending for some 280m across the west side of Cothelstone Hill, with an intermittent ditch, 2m wide and 0.8m deep on the east side. One notable characteristic of the monument was its symmetrical form, created by both the northern and southern ends diverting to the west.

English Heritage plan of the earthworks on the western end of Cothelstone Hill.


Immediately prior to the commencement of the dig, however, we received the results of a high-resolution LiDAR survey which we commissioned of the entire LPS area. LiDAR (Light Detection and Ranging) is a remote sensing technique which uses laser scanners, mounted on an aircraft, to produce high-resolution landscape surveys. These measurements are then processed, to provide accurate measurements of the ground surface which are in turn used to create detailed 3D maps known as Digital Terrain Models. These results had a startling impact on our excavations at Cothelstone Hill, as they clearly showed the continuation of the earthwork along the southern and western sides of the hill’s western spur. Although less distinct, this boundary could also be seen to continue beyond a medieval east-west field boundary, beneath extremely dense vegetation. This new information suggested that the earthwork constitutes part of a hilltop enclosure, rather than being a linear feature. The hope was that the excavations could help us to date this exciting new discovery.

LIDAR image of the western spur of Cothelstone Hill showing the new extent of the earthwork and the presumed northern line (in yellow). The excavated trenches are shown in red.


Two trenches were excavated across the eastern side of the enclosure, revealing the ditch to extend to a width of 4m wide and a depth of 1m. The bank had been fronted with a dry-stone wall, 1.2m wide, comprised of the local stone dug out of the ditch; this wall appears to have collapsed into the ditch relatively soon after its construction. Evidence of a void behind the wall may represent a slot for a horizontal timber beam which acted as a baseplate for vertical posts. When the timber rotted away the surrounding material dropped into the resulting void.

For most of our volunteers, this was their first experience of archaeological excavation, and it was something of a baptism of fire.  During the first week they worked through Britain’s first extreme heat warning, with temperatures that made any physical activity extremely tiring. The middle Saturday was lost because of the threat of lightning storms; and frequent downpours hampered work during the second week. Nevertheless, the volunteers did a sterling job, remaining enthusiastic despite the challenging conditions and the not always immediately rewarding archaeology.


Unsurprisingly, finds were few and far between. In total an assemblage of 25 flints was recovered from the two trenches, probably representing material from earlier periods that was already present in the soil when the earthwork was built. A very small number of pieces of pottery were found, the best example being a rim shred, from a charcoal layer in the ditch, which was initially estimated to be of Iron Age date, thereby lending support to the belief that the earthwork itself was an Iron Age construction. However, several charcoal samples were recovered during the excavations and sent for carbon 14 dating. The results of these tests have now been received and suggest a date for construction of the enclosure in the Late Bronze Age, sometime between 907 and 836 BC, with later activity on the site in the Iron Age, as evidenced by the pottery find.

This has led to an identification of the enclosure as a ‘slight univallate hillfort’, a classification of monument of which the 150 sites known in England are considered to be of national importance in helping to improve understanding of the transition between Bronze Age and Iron Age communities in Britain. Slight univallate hillforts remain enigmatic features in the landscape, having been variously interpreted as stock enclosures, redistribution centres, places of refuge and permanent settlements. To help better understand the kinds of activity taking place at Cothelstone Hill, we will be returning to undertake geophysical survey of the interior of the enclosure in 2022.