2017:284 - Portraine Demesne, Dublin

The site was identified during a monitored topsoil strip (Licence Ref:17E0210) in advance of construction of the NFMHS Hospital on the St Ita’s Hospital Campus in Portrane, Co. Dublin. The site was found on 8 May 2017 and given a preliminary identification as a Burnt Spread/Mound defined by characteristic fire blackened soil and shattered stone fragments. Preservation by record was carried out between 31st July and 5th September 2017 (licence Ref: 17E0377). An area was stripped by tracked excavator and topsoil cover reduced by hand to define the full nature and extent of the site.

Initially the site was dominated by the burnt spread (F6), of blackened clayey silt, black in colour with a high frequency of shattered stone. Further to the northern limits of the spread it became considerably shallower in depth and paler through leaching by water over time. The original watercourse was identified to the north as an irregular, shallow band of yellow-grey clay running east to west across the northern side of the excavation (F53 & F48).

To adequately record the form of the burnt spread (F6) an east-west base line was established, dividing the spread into northern and southern areas. 11 trenches, 1 metre in width, were defined crossing the spread from its northern to its southern limits. Alternate trenches were excavated north and south, giving continuous north to south profiles through the F6 material and partially exposing any cut features sealed by the burnt spread.

The burnt spread (F6) was crossed from east to west by a series of 4 parallel linear features, from the south; F83, F3, F9 and F19. All four linear features cut through the F6 burnt spread material and stratigraphically post date the burnt mound activity. To the north of the burnt spread were the remains of a metalled / cobbled surface (F92). This may be the remains of a trackway leading from the farm buildings to the east of the excavation to the location of a horse operated Warner pump to the west.

The burnt mound (F6) was also disturbed by evidence for later agricultural activity in the form of linear features and furrows / land drains. These features were in line with the slope, running roughly south to north. Two other anomalous features were noted peripheral to the burnt spread. F37, a sub oval ‘pit’ was noted northwest of the F6 spread. While its main fill consisted of dark grey silty clay and shattered stone fragments it displayed a figure-of-eight form at its base, reminiscent of a kiln. A second possible kiln, F28 was located due south of F37. Keyhole shaped in plan and orientated from east to west, its basal fill (F63) contained no burnt mound material.

Beneath the burnt spread (F6), several features were noted. These included two depressions/pits likely for water management (F32 and F13) with a linking channel / leat (F42). Also, of note was the sub-circular slot trench (F7) which was indicative of a standing structure. An extensive cluster of 108 stake holes and several postholes add to the evidence of activity on the site. The excavation suggests that there was more than one use period represented. The water management features all show evidence of alterations or recuts.

The sub-circular slot trench (F7) enclosed an area measuring 4.00m (E-W) by 4.30m (N-S). The base of the slot trench (F7) undulated at the positions of upright stakes, small posts or planks forming an enclosing structure. While a number of post and stake holes are associated with the slot trench (F7) they do not appear to have supported a substantial roof structure, if any. The area within and outside of the slot trench (F7) on the north western side displays a scatter of 108 stake holes. Some of the stake holes may have cut or been cut by the slot trench (F7) but the similarity in fills makes it hard to state definitively.

To the north of the sub circular slot / possible foundation (F7) is F32 which appears to have been designed to serve as a well / reservoir for water. The pit (F32) is sub-circular in plan, 1.20m in depth and lined with a layer of light grey clay (F41). Contained within this ‘liner’ were preserved plant fibres which may have served to reinforce or retain the clay liner during construction.

1.20m north of F32 was F13, a sub-rectangular pit which measured 2.40m (E-W) and 1.90m (N-S) and reached a maximum depth of 1.78m. The sides of the pit were stepped in before dropping vertically to the base. The near vertical sides of F13 were lined with a beautifully made circular, wattle structure 0.90m in diameter and 0.50m in height.

The site produced a surprisingly large quantity of lithics, including cores and hammer stones. Samples from the various structural features are currently under analysis and it is hoped that sufficient archaeobotanical remains will be present to give C14 dates for the site.

35 Brook Meadow, Avoca, Co. Wicklow