2006:1164 - Derryvorrigan 1, Laois

This site was identified during testing along the route of the M7 Portlaoise to Castletown/M8 Portlaoise to Cullahill motorway scheme. The excavation revealed a scatter of settlement located on the north side of Knockseera hill that extended along a level ridge for a length of c. 140m east–west, towards the base of the hill. The features identified included four subcircular structures and a scatter of pits, post-holes, stake-holes, a charcoal-production pit and a post-medieval limekiln.
At the east side of the ridge, the first of these circular structures was excavated. It comprised fifteen post-holes that formed the outline of a subcircular arc. These post-holes varied in size but were mostly circular in plan with rounded or tapered bases. It is likely that they may represent the remains of a round house; unfortunately, the north-eastern section of this arc was destroyed by recent activity in the area. A hearth was located within the centre of the arc and several small stake-holes were excavated around the edge. West of this structure, at a distance of c. 40m, was a complex of pits, post-holes, a metalled stone surface, three single bowl furnaces, three figure-of-eight bowl furnaces and a shallow drain. Iron slag was recovered from the bowl furnaces and several of the pits. Slag was recovered from one of the post-holes in the subcircular structure. At the west side of the ridge, c. 40m from the complex of pits, the second subcircular structure was uncovered. It was less than 3m in diameter and delimited by 43 stake-holes. Internally, four post-holes and a shallow pit were recorded. This structure may have been an animal pen or a small ancillary building. West of this structure, at a distance of 25m, a third structure was uncovered consisting of eight shallow post-holes arranged in a circle with a diameter no larger than 2.5m. This structure may be associated with the fourth and largest structural complex, 5m to the south. This structure measured 11m in diameter and was formed by a series of post-holes. The complexity of the archaeology associated with this structure, over 40 post-holes, lines of stake-holes probably representing internal divisions and curvilinear slot-trenches, suggests that there were several phases of use associated with this structure.
North of this complex was a cluster of six circular shallow pits. No evidence of ironworking was recorded from this area of the field and the only find retrieved was a blue glass bead from one of the post-holes. To the south in the adjoining field a charcoal-production pit was excavated.
Within this field, to the south and midway between the two areas of archaeology, a post-medieval limekiln depicted on the first-, second- and third-edition OS maps was recorded and excavated. The kiln was c. 4m in diameter, constructed of large subrectangular limestone slab (external) and small square limestone blocks (internal), with an arm on the north-east and north-west corner supporting the face of the kiln. The kiln was set into a hollow south of and close to the south boundary ditch. The kiln, ditch and trackway were located in situ, as identified from the OS maps. Another post-medieval feature uncovered within this area was a field ditch measuring 1m wide by 0.5m deep. It crossed the site in a north–south direction, exiting at the adjoining field boundary to the north. Two small stone-filled drains emptied into this ditch. At the western edge of the site another field drain ran in a north-east/south-west direction across the site.
Post-excavation analysis of this site is still ongoing.