1996:126 - ISALNDBRIDGE: Hospital Lane, Dublin

An initial assessment had been conducted by Tim Coughlan on this site on 15 February 1996. However, owing to the presence of upstanding buildings and a large marshy area to the north-west of the site, the total area available for testing was severely reduced. The second phase of testing was carried out on 15 July 1996.

During the five months that had elapsed between the two assessments most of the upstanding buildings had been demolished, with the exception of several walls in the southwest corner of the site. The dry weather had allowed the marshy area to dry out sufficiently to allow machine testing.

The site is located along the south bank of the River Liffey at Islandbridge. There are references to mills in the area from 1566, and a mill-race is recorded on the site. At present the line of this mill-race appears to have been marked by the line of an existing boundary wall running across the site north-east/south-west.

Three trenches were opened in the southern area of the site along the line of the recently demolished building. No surviving archaeological material was found owing to the severe ground disturbance from foundation walls and basements.

The boundary wall as it existed during this assessment stood some 1.8m high along its western face; the ground had been built up with a sterile brown clay within the eastern face of the wall and was almost level with the top of the wall as it then stood. The upper course of the wall as noted by Coughlan had since been demolished—but this, as pointed out, had been an obviously later addition. On initial inspection the wall was thought to be constructed from huge lime-stone blocks, roughly dressed and without mortar. The western or outer face was steeply angled, forming a batter. The wall was investigated in two places and was seen to be bonded with mortar, with the suspicion of red brick in section.

A second wall was discovered below the ground surface to the west of the upstanding wall and was discovered to be of the same limestone block and mortar construction. Because of the remarkably similar appearance and construction technique of the two walls, it can be concluded that they are contemporary and associated in some way. All finds from the clays abutting the walls were of nineteenth/twentieth-century date and clearly do not date back to the late medieval mill-race.

In Coughlan’s first assessment he noted that a second wall ran along Clancy Barracks, bounding the Liffey. He noted that the upstanding wall on the site had continued eastwards as an inner boundary wall of the barracks, and had postulated that perhaps this wall was the inner or eastern wall of the mill-race. In the light of further investigation, it would appear likely that the second wall uncovered is a continuation of the outer boundary wall along the barracks and may not be directly associated with the mill-race. While it is plausible that the line of the eastern wall of the mill-race was reused as a much later boundary wall, there was no direct surviving evidence for this earlier mill-race.

Power House, Pigeon House Harbour, Dublin 4