2012:020 - Calhame: A8 Dualling, Areas D3, D7 and D8, Antrim

This site was part of the A8 Belfast–Larne Road Dualling Scheme. The scheme was test trenched (licence AE/12/096) and areas containing possible archaeological features were expanded to discover the extent of the archaeology. A new licence was then granted to excavate these areas of archaeology; Areas D3, D7 and D8 were excavated under one licence due to their close proximity.
Sites D3, D7 and D8 were situated between the Calhame Road and the Legaloy Road on the eastern side of the A8 on undeveloped farm land. Whilst Area D7 was located in a small hollow in the landscape, Areas D3 and D8 were at the same level. The subsoil in Area D3 was a glacial till. Areas D7 and D8 also sat on glacial till but it underlay a thin layer of river-deposited clay which covered a large area around the palaeo-channel.
The southernmost of the three areas, Area D3, consisted of six pits (C900, C903, C906, C912, C918 and C921) all of which contained large buried stones.
At 112m north north-west of Area D3 was Area D7, a burnt mound (Burnt Mound 1 - C1000) and associated trough (C1009). Rectangular trough C1009 was located under the south-western side of the burnt mound and contained the remains of wooden posts in three of four corners and a drain exited through its fourth.
At 162m east of Area D7 was Area D8, a further two burnt mounds (Burnt Mound 2 - C1016 and Burnt Mound 3 - C1018) with a trough (C1020) under the north-eastern side of Burnt Mound 3.
Running between Areas D7 and D8, and between Burnt Mounds 2 and 3 in Area D8, was an ancient palaeo-channel. When active this channel would have formed a river and is undoubtedly the reason the burnt mounds were situated where they were.
There are two possibilities for the stones in Area D3, either buried prehistoric standing stones or recently buried field stones. The size of the stones ranged from 0.66m to 1.08m in length with their average width being 0.79m. These are reasonably small, however small stature standing stones are not uncommon in Northern Ireland, although they are mostly found in the west and north-west of the country. Although these could not be dated directly their close association with a Neolithic and Early Bronze Age site suggests that they were indeed prehistoric. Although no socket was identified for any of the stones this is not unexpected if they were to be buried. The easiest way to bury the stones would have been to dig a large pit next to the stone down its base and then push the stone over. Any packing stones could then have been placed around the main stone and the whole thing covered. This would account for what was uncovered on site: a series of pits with individual large stones surrounded by smaller stones.
One problem with the stones having been standing stones is the lack of any weathering on the surfaces. If the stones had been standing for any period of time weathering on the surface should have been evident. This would suggest that the stones were erected, and then collapsed and buried in a relatively short period of time.
While it is possible that the stones were the result of post-medieval field clearance, an example of a buried standing stone had already been uncovered during monitoring on the A8 Road Scheme approximately 1.7 miles to the south, in the area of the main site compound. Along the remainder of the proposed route the lack of large stones present in the subsoil had been noted, it being apparent that most had been used in farm wall construction. It also seems highly unlikely that these stones were the result of field clearance if the size of the stones and the nature of their burial are taken into consideration.The stones are not that large and could easily be moved away if proving troublesome. Secondly, a number of the stones protruded up into the topsoil; this would hardly be an improvement if that was the aim. Finally, packing small stones around the larger stones to create a defined setting is not the work of somebody simply clearing a field.
As no artefacts were found within any of the pit fills of the features, we are therefore unable to date them.
Areas D7 and D8 contained between them three burnt mounds. Burnt mound 1 consisted of a mound C1000, F1001 and F1002 (c. 28.2m3) and wood-lined trough C1009 (c. 0.95m3). Burnt mound 2 consisted of a mound C1016 and F1017 (c. 8.71m3) and finally Burnt mound 3 consisted of a mound C1018 and F1019 (c. 18.16m3) and trough C1020 (c. 1.43m3).
The majority of the stones excavated from the mounds and troughs were burnt, heat-shattered basalt. Experimentation by Buckley (1990, 171, table 1) has shown that, for example, sandstone can withstand up to five heatings and dowsings before breaking down into non-reusable fragments. Similarly, limestone was shown to withstand six such actions, with harder stone types requiring significantly more. However, Buckley’s experimentation indicated that basaltic stone can withstand up to 20 heatings and dowsings before becoming unusable, while vesiculated basalt withstood 25 actions without breaking down sufficiently to be discarded. The implications of this work for the A8 sites in Areas D7 and D8 is that the stone, which was predominantly basalt (unknown if this was normal or vesiculated), must represent at least 20 individual firings. If, for example, the largest trough, C1020 (c. 1.43m3), is divided into the estimated surviving volume of the mound, C1018 (c. 18.16m3), it suggests a minimum of 12 separate firings. If the same calculation is preformed using the capacity of the smaller trough C1009 (c. 0.95m3) and its mound C1000 (c. 28.2m3) it would suggest a minimum of 29 episodes of use. Although such basic calculations are fraught with difficulties and beset by caveats, this is still likely to represent a remarkably conservative estimate for the minimum number of firings given the likely damage done to the mounds over time. While this may seem a relatively large number of uses, it pales into insignificance when compared to sites such as Killoran 265, Co. Tipperary, which showed evidence for up to 615 firings, and especially Killoran 240, Co. Tipperary, which was calculated to have been fired in excess of 3000 times (Cross May et al. 2005, 218-9). Thus, the evidence provided by the A8 troughs is that of a relatively short-lived site that functioned for a restricted period before being replaced or superseded by another in the locality. Nonetheless, it is likely that, during its albeit brief lifespan, this site would have been an important and conspicuous landscape locus for the area.
Post-excavation work is in progress and the full report should be available by the end of August 2013.

References:
Buckley, V. M. 1990 ‘Experiments using a reconstructed fulacht with a variety of rock types: implications for the petromorphology of fulachta fiadh’ in V. M. Buckley (ed.) Burnt offerings: International contributions to burnt mound archaeology. Dublin. 170 – 172.
Cross May, S., Murray, C., Ó Néill, J., & Stephens, P. 2005 ‘Catalogue of dryland sites’ in M. Gowen, J. Ó Néill, & M. Philips (eds.) The Lisheen Mine archaeological project 1996 – 8. Bray. 283 – 310.

Northern Archaeological Consultancy Ltd, Farset Enterprise Park, 638 Springfield Road, Belfast, T12 7DY