2005:520 - RATHFARNHAM: Rathfarnham Castle, Dublin

The Parks and Landscape Services Department of South Dublin County Council proposed to develop a formal garden within the grounds of Rathfarnham Castle. The site was bounded by Castleside Drive to the north, Rathfarnham Road to the west and by walls to the south and east.

Monitoring was carried out over six days between 17 and 25 October 2005. The area was excavated using a thirteen-tonne machine fitted with a 1.8m-wide toothless bucket.

The development area consisted of a flat field measuring c. 70m east–west by 45m. All topsoil was mechanically excavated to the level of geologically deposited strata, with the exception of a band measuring c. 3m wide on all four sides of the development area which was used to store topsoil. The development would not involve excavation in this area as it would be built up to create landscape mounds and as a result there would be no impact on any archaeological remains.

Monitoring revealed the site to consist of topsoil directly sealing geologically deposited clay. Topsoil was on average 0.5–0.65m deep and consisted of a loose dark-brown silty clay with occasional small stones (20–50mm) evenly distributed, along with occasional finds of small clay-pipe fragments, modern bottle glass, china pottery fragments and red brick. Further finds included plastic bags, wire, several large pieces of compacted metal and the remains of two separate car seats. These modern finds were revealed across the whole of the site, but the north-west corner contained the majority of the modern material.

It was noted by a number of local people that topsoil was imported and dumped into the site c. 20–25 years ago. As there was no evidence for a relict ploughsoil or topsoil under the imported topsoil, it is considered that the site was fully stripped at the time of importing the modern topsoil and that this stripping probably extended into the natural subsoil, which would have removed any subtle archaeological features.

Natural was a friable to compact light-brown clay with occasional small stones (20–50mm) evenly distributed. Limited mechanical excavation into natural to ensure that it was a geologically deposited strata and not a redeposited soil revealed a much more stony layer 0.1–0.15m below it, but this was also in the same friable to compact light-brown clay matrix.

Two modern stone-filled drains were revealed. Drain 1 extended north–south across the stripped area, extending beyond the area of excavation in both directions. It was 1.4m wide and was cut into natural to a depth of 0.9m. It was sealed by a loose rubble layer containing small red-brick and mortar fragments which in turn was sealed by topsoil. It appeared to be dug by hand and was filled with on average 0.2m by 0.15m by 0.1m angular to sub-rounded stones. Drain 2 extended west off Drain 1 at a right angle at a point 3m south of the northernmost area of stripping and extended beyond the area of stripping in a westerly direction. This drain was 0.9m wide and 0.95m deep as cut into natural. The drains did not truncate one another but appeared to be contemporary. The fill of Drain 2 was the same as Drain 1 and again it was sealed by a loose rubble layer containing small red-brick and mortar fragments, which in turn was sealed by topsoil.

No archaeological features or objects were revealed as a result of the monitoring.

Dame House, 24 Dame Street, Dublin 2