2014:354 - CLS139, Cloonshannagh, Cloonshannagh Bog, Roscommon

Cloonshannagh Bog is located 3km north-west of Termonbarry and 2.5km west of Lough Forbes. The bog is part of the Bord na Móna Mountdillon Group and has a total area of 331 hectares. A survey by ADS in 2008 under licence 08E0645 identified a total of 88 sites. Upon re-assessment by ADS in 2013 under licence 13E0221 89 sites were recorded. Of the 89 sightings, 60 were platform sightings, 18 sightings were of archaeological wood and 11 were trackway sightings, all of varying lengths and widths. Of these 35 sites were listed for excavation as part of the current contract.

The location of site CLS139 was identified using survey-grade GPS equipment and a 4m by 3m cutting was opened. The peat above the site consisted of a reddish orange poorly humified (H1-H2) sphagnum-rich peat with macro components comprising eriophorum (south and east sides) and calluna (north side). Following oxidation the colour changed to mid-dark brown.

The site consisted of a number of layers of wood. The uppermost layer was constructed of longitudinally laid brushwoods with occasional transverse brushwoods. The wood was not particularly densely laid, although it may originally have provided a more densely-packed surface. The preservation is poor to moderate with some worked ends visible, but also many broken and damaged woods. The peat around and within the wood differed from that above the site in being strongly decomposed (H4). It was a sphagnum type peat with inclusions of calluna and patches of grass and eriophorum.

The upper layer of wood may represent a repair or later structure built on top of the main structure as the two were separated by a clear layer of peat suggesting the main structure had been well inundated. The intervening peat layer was sphagnum-rich and strongly decomposed (H4) and contained moderate inclusions of grasses and eriophorum throughout and was generally 0.1-0.15m deep.

The main structure consisted of a mixture of brushwood (25%) and roundwood (75%) elements. The brushwood appeared to have been generally thrown down first, as a foundation layer to support the longer and more substantial roundwoods although it remained quite mixed possibly indicating that the smaller brushwoods had shifted and broken under the weight of the larger roundwoods. The roundwoods were quite tightly packed compared to the brushwoods which were more spaced. The general condition of the wood was moderate to good with many of the roundwoods retaining bark and having clearly identifiable worked ends. The roundwoods ranged in size from 0.6–3.63m in length and 0.08–0.2m in diameter with the brushwoods being 0.03–1m in length and between 2–7mm in diameter. The peat within and around the wood was dark orange-brown in colour, sphagnum-rich with inclusions of eriophorum mainly around the wood. The peat had a relatively high content of wood chippings and rooty material, due to the proximity of the structural timbers and it was very strongly decomposed (H4-H5).

Located centrally within the cutting, a deposit of brushwood was recorded beneath the main structure following its removal. These brushwoods were laid generally longitudinally and were very poorly preserved and heavily broken by the weight of the structure above and had the appearance of a layer of wood chips within the underlying peat. They represented a sub-structure layer possibly laid in a pool to provide support although the wetter pool may have been created by the weight of the timbers above on the underlying peat - a strongly decomposed sphagnum-rich peat.

A fragment of birch, 22 yrs, was chosen for AMS dating from samples taken from the 2013 ADS survey and returned a result 798–541 BC.

Interpretation / discussion
This site was originally recorded as a possible platform, although the size and orientation of the elements would suggest that it represents an east-west orientated trackway, although further sightings cannot be confirmed, possibly due to its depth below the field surface.

IAC Ltd, Unit G1, Network Enterprise Park, Kilcoole, Co. Wicklow