2001:471 - SUTTON, Dublin

In the course of dredging works associated with the laying of submarine pipes across Dublin Bay from Ringsend to Sutton, a discrete stony feature was exposed on the eastern side/shore of the excavated pipeline trench. The site is exposed on a sandy island at low tide at Sutton Creek, Sutton, Co. Dublin. A test excavation to ascertain its nature and extent was carried out.

The site, accessible at low water, comprises a small stony feature on the eastern side of the excavated pipeline channel. It extends as a simple irregular cluster or spread of sandstones, some 6.2m by 3.2m. None of the stones appeared water-rolled or abraded. Only recent and minor sea grass adhered to the feature. Indeed, the virtual lack of any marine encrustations or sustained plant accretions suggests that either the feature has only recently been deposited there or that it has become visible only after impact by the dredging works. The stony or rocky feature is situated some 370m to the north-west of the newly discovered Sutton wreck (see Excavations 2001, No. 472).

Two baseline profiles were set up at right angles that traversed the feature on its short and long axes and were plotted by EDM from across the channel. The feature was then drawn and photographed. A 4m by 1m trench was excavated along the short axis baseline. The trench extended from the edge of the channel through and beyond the feature by 1.5m and was excavated to a maximum depth of 0.3m. The stones comprise irregular hewn sandstones with an average size of 0.4m by 0.3m. They are disposed in a general rectangular fashion without any attempt at formality or construction. The stones were removed by hand and the remaining sandy fill was removed by trowel and spade. The stones did not overlie any other stones or features and lay as they were originally left. The excavation of the trench was undertaken over three tidal opportunities with unfortunate total infilling of sand by marine activity between tides.

A 20m-radius line was extended from the eastern point of the short axis baseline. A curving arc was drawn in the sand, demarcating the limits of the investigation, and was physically marked and plotted with an EDM. This zone was investigated by metal auger to an average depth of 0.63m, with radiating test-holes undertaken every 0.5m for a distance of 4m and reduced to 1m separations up to a limit of 20m. The most proximate or potentially sensitive auger holes were also plotted by EDM. As the augering continued to produce negative results, electronic plotting was discontinued. Ultimately the extent of the exposed stony feature was confined to the physically visible mapped limits.

The results show that the feature consists of a single stony deposit associated with one single event that was covered in sand by tidal action almost immediately. The stony feature was then uncovered in the course of the dredging works associated with the submarine trench excavation. It was not possible to date the original deposition but it is most likely that the stones represent the discharge of ballast from some vessel in an effort to disengage from the sand.

3 Canal Place, Tralee, Co. Kerry