2007:461 - DUBLIN: Clarke Square, Collins Barracks, Arbour Hill, Dublin

Monitoring of five engineering test-pits excavated at the north-west corner of Clarke Square in Collins Barracks was undertaken by two archaeologists on 22–26 February 2007. The works were carried out as part of an overall assessment for the proposed site of an exhibition gallery for the yacht Asgard.

The remains of a small section of limestone slab floor surface were observed within Test-pit 3, which abutted the southern face of the retaining wall extending along Arbour Hill. This floor surface consisted of a number of large stone slabs covering an area c. 0.9m wide and 1.5m long. The stone slabs were c. 0.1m in breadth and were set within a mortar and brick bedding layer 0.2m deep. A linear drain or gully was exposed 0.8m to the south of the slabs, orientated in a north–south direction, with its northern extent truncated. The test-pit was excavated to a depth of 1.05m beneath the existing ground surface. The Arbour Hill retaining wall extended to a height of 2.8m from top to base. The possible floor surface was exposed 0.15m above the base of the retaining wall foundation. The flat stone slabs were set abutting the Arbour Hill retaining wall, indicating that they were a later insertion. A rectangular building is depicted in this area on the 1866 OS map; it appears to have been constructed some time between 1847 and 1866. No finds were recovered from within the features to confirm this date.

Test-pit 5 was located in an enclosed raised area, south of the terraced garden and north of a flight of steps abutting a stone retaining wall which forms the eastern boundary of this area. A section of a wall foundation was exposed between 0.55m and 1.2m below the existing ground level. This was constructed of undressed stone and poorly bonded lime mortar, randomly coursed, consisting of two distinct but abutting walls forming an ‘L’ shape, suggesting the foundation was located at the south-west corner of the building, possibly contemporary with the floor surface exposed in Test-pit 3. The stratigraphy of the site and the cartographic evidence would indicate that these features appear likely to be of late 18th- or 19th-century date; no finds were recovered from within the wall foundation to confirm this date.

The remaining three pits (Test-pits 1, 2 and 4) were located within the elevated garden terrace and adjacent to the modern link building and lift shaft. The three pits contained no features, structures or artefacts of historical or archaeological interest.

The structural features visible within Test-pits 3 and 5 were fully recorded before they were backfilled. The features were exposed for a short time only and were not impacted upon by the investigative works. They remain in situ for further investigations, should the proposed development proceed.

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