Taking a Tour with Tom
January 31, 2023Recording the North Cairn Radar Station
March 21, 2023The Mull of Galloway, Scotland’s most southerly point, has long been something of an archaeological mystery.
The thousands of visitors that make the journey to the dramatic peninsula are mostly unaware that, as they travel onto the Mull, they pass some of the most substantial earthwork fortifications found in the Rhins, the remnants of an ancient defended enclosure. Archaeologists have known about these defences for over one hundred years, but the date of their construction and their function have remained obscure.
Part of the uncertainty arises from the fact that the two earthworks, which are drawn across the neck of the promontory at East and West Tarbet, are very different in character. The western rampart is shorter but much taller, standing over 3m in height, while the eastern rampart comprises a series of banks and ditches, all under 1.5m in height, taking a sinuous path over the hillside beyond the narrow neck at East and West Tarbet. Doubt was placed on the date of the features when the site was mapped by the Ordnance Survey in the mid 19th century, when the eastern rampart was considered to be of relatively recent date, perhaps an old field boundary, whereas the western structure was depicted as an ancient fortification.
Excavations carried out in the early 2000s had shown that both ramparts were multi-phase constructions, involving fortification and refurbishment, re-digging of the ditches and addition of new banks and palisade fences. However, a lack of surviving organic material in any of the structures or soils meant that it was not possible to obtain radiocarbon dates from either rampart, meaning that the date of their construction was entirely unknown. You can hear more about the site in this talk by Graeme Cavers of AOC Archaeology.
So are the Mull earthworks prehistoric, post-medieval, or somewhere in between?
As part of the Rhins Revealed project, new excavations were carried out at the earthworks, aiming to record areas of the ramparts being affected by erosion and in the hope of obtaining new samples that might allow their construction to be dated. Two trenches were excavated by archaeologists from AOC with a team of volunteers from across the Rhins. The new excavations and volunteering opportunity was made possible with grant assistance from the Historic Environment Scotland Support Fund.
Our new excavations revealed new detail about the construction of the banks, and confirmed previous observations that they comprise multiple periods of building and rebuilding. We were lucky to be able to work with Dr Tim Kinnaird of the University of St Andrews to collect new samples for a dating technique called optically-stimulated luminescence (OSL). This approach is different to radiocarbon dating, and while less precise, can give an indication of construction dates where organic materials don’t survive, by estimating age based on the last exposure of sediments to light. When we have the results of this new analysis, we may have the first evidence for the age and history of the enigmatic fortifications.
We’ll report back here soon. Watch this space!