1999:263 - ROBSWALL, Portmarnock, Dublin

Archaeological field-walking and test-pit excavation were carried out at the site of a proposed development north-west of Portmarnock, Co. Dublin, on 27 September 1. The site is in Robswall townland, c. 350m west of the coast road and 160m north of Portmarnock village. The proposed development site is within an area of pasture, with a school immediately adjacent to the south-west. The site is between two recorded archaeological sites: a holy well (SMR 12:38) 350m east of the development and a flint scatter (SMR 12:37) c. 140m south-east of the development.

Between 1964 and 1983 a collection of around 2500 prehistoric artefacts was made from this area. It seems likely, however, that this collection contains material from a wider area than it is actually attributed to. In this respect it would include some of the fields on which the proposed development is to be constructed. The quantity of flint recovered from this area led to an excavation of the site in 1983 by David Keeling, 200m north of the proposed development site. A substantial collection of lithic material was recovered from the ploughsoil; however, only scant remains of archaeological features were found cut into subsoil. Two of the features contained charcoal, which gave radiocarbon dates of c. 2000 BC. The excavation concluded that intensive ploughing had removed or truncated most of the subsurface archaeological features and in so doing had transferred most of the archaeological material into the ploughsoil. Recent field-walking by Avril Purcell before the development of a site 400m to the north on the coast road recovered a quantity of worked flint (see Appendix No. 1).

The site consists of two fields, of which the western had been ploughed to facilitate field-walking. An initial site inspection on 23 August 1999 recovered several fragments of natural flint, sherds of late 19th-century pottery, red brick fragments and an iron nail. Before this visit a strip c. 5m wide, running the entire length of the field, had been stripped of topsoil (maximum depth 0.5m). An access road was being constructed west of the ploughed field, requiring the removal of topsoil and the insertion of a drainage pipe. An inspection of these works revealed a limited depth of topsoil in this area and a thin layer of brown clay overlying rocky outcrops.

Archaeological field-walking and test-pit excavation on 27 September 1999 revealed a flint scatter in the north-west corner of the field, lying largely beyond the area of development. Six 1m2 test-pits were excavated within the ploughed area, their location based on the density and type of lithic material present on the field surface. The material from the test-pits was passed through a sieve to recover lithic and other material. No soils or features of archaeological significance were identified during test-pit excavation. In general the material recovered reflects variations in the natural geology of the area. The test-pit results suggest limited archaeological potential within the proposed development area.

A low-frequency concentration of flint was noticed within the higher, north-western area of the ploughed field. This area is immediately west of the proposed development. The eastern side of the field had been partially stripped of topsoil that had been banked along the eastern and southern edges of the field. A single end scraper of fairly good quality was recovered from the edge of the remaining section of the ploughed field at a location c. 10m south of the north-lying field boundary. The greatest concentration of flint was found in the north-west area of the ploughed field, corresponding with its highest location. There was a marked fall-off in both the number (frequency) and quality of the flint material to the east, south-east and south of this area. One must conclude that, purely on the basis of the material recovered, there is a low-frequency rate of diagnostic artefact types to that of rubbish and flint spalls, even in the higher, north-west area of the field. The lithic material was evenly distributed throughout the first 0.2m of the topsoil in each of the test-pits, with frequency decreasing with depth. No lithic material nor any indicators of archaeological activity were observed within subsoil at the base of the test-pits. However, this does not preclude the existence of such features, even in truncated form within the field.

2 Killiney View, Albert Road Lower, Glenageary, Co. Dublin