County: Dublin Site name: PORTERSTOWN
Sites and Monuments Record No.: N/A Licence number: —
Author: Claire Cotter
Site type: Ring-ditch
Period/Dating: Bronze Age (2200 BC-801 BC)
ITM: E 706142m, N 736862m
Latitude, Longitude (decimal degrees): 53.371282, -6.404968
In 1988 planning permission was sought from Dublin County Council for the development of a car park at St Mochta's Church, Porterstown, Co. Dublin (c. 3.5km west of Phoenix Park). It was intended that the car park, roughly 1 acre in extent, would be situated in the north-west corner of what is at present a large potato field.
An oblique aerial photograph taken in July 1968 by the University of Cambridge revealed traces of an almost circular cropmark in the north-west corner of the field. As a result archaeological excavation was recommended by the Office of Public Works.
Prior to excavation, no trace of any feature associated with the site was evident. The cropmark was mapped out onto the field from the AP and a north-south and a east-west trench excavated through the centre.
The ditch visible on the AP was located in three places viz; along the north, south and east. The western limit of the site may lie beyond the present field boundary. The ditch was round bottomed, 2.5m-3m wide at the lip and narrowing to 0.6m at the base. The excavated sections were up to 1.25m in depth but had been truncated by ploughing. With the exception of a single charcoal-rich layer in the south section, the fill throughout was sterile and consisted of silty, stony clay. Two fragments of animal bone were recovered from the charcoal layer.
No trace of any ancillary features associated with the ditch were revealed in the course of the excavation. Possible evidence for a break in the ditch may be detected in the east sector of the site on the AP.
Slightly under 10% of the interior was excavated. No cultural layers were preserved and the extant features were heavily truncated. A curvilinear gully and three scattered postholes (0.15m diameter x 0.25m deep) were revealed. The southernmost posthole yielded a sherd of Bronze Age pottery. The sherd had no visible decoration and is too fragmentary for close identification.
No stratigraphical evidence survived to assess the relationship between the internal features and the ring ditch. The curvilinear trench or gully and the scatter of post-holes are features paralleled on a broad range of sites - both funerary and habitation - dating from the Bronze Age onwards. In the general Porterstown area Bronze Age settlement is attested to by the discovery of EBA cists in the Phoenix Park in the last century, the ring barrow complex which survives near Clonsilla, and the Middle Bronze Age sites along the Liffey basin.
The large size of the enclosure itself (34.5m internal diameter) suggests that it may have been a ringfort. The overall diameter and the location of a possible entrance feature in the east-south-east sector comply well with other sites of this type in the north Dublin area. Furthermore the location of the site accords well with the distribution of ringforts rather than the more southerly distribution of ringbarrows etc.
1 Northbrook Villas, Northbrook Road, Dublin 6
