2008:494 - Sutton to Howth, Dublin

Monitoring was undertaken along the route of a new sewer pipeline from the Offington Estate in Sutton to the village of Howth, forming the main part of the 2.6km development that included the construction of a new pumping station and a combined sewer overflow and storm tank.
The pipeline passed through the constraint zone of the national monument of St Mary’s Church and it was initially recommended that test excavations be carried out in all areas of the development within a 100m radius of the church and that monitoring and periodic inspection be carried out along the remainder of the contract. A report on the testing phase of the operation concluded that no material of any great archaeological significance survived in the vicinity of the national monument (Excavations 2006, No. 660).
The monitoring and inspection of the remainder of the works was carried out by the writer and Peter Kerins from March 2007 to February 2008. Little of archaeological interest was discovered over the length of the trench, excavated to a width of barely 1.5m and to a varying depth. The remains of a shell midden, at least 1.5m in length and 0.25m in depth, were disturbed on the northern side of the trench c. 25m west of the junction with the road into the Offington Estate. The midden was composed of small cockleshells, some of which had been crushed. It was located on flattish ground at the base of a gradual rise in ground levels and associated with an accumulation of reddish-brown sand.
The stratigraphy here is suggestive of there being an old inlet or creek over the area when the sea levels were higher. The present foreshore is c. 150–200m north of this trench, beyond the railway line and the seafront properties on the Burrow Road. As the sea level dropped or was deliberately excluded, a fine reddish-brown silt accumulated over the coarse sands and gravel. At some point early in this process the harvesting of shellfish resulted in the build up of waste shell product.
Although the find site was located some 200m away, a shell midden has been recorded in the townland (DU015–024). The midden was fully excavated in 1949 and 1970. It contained shallow pits that produced animal bone material including dog, fish, pig and bird, and flint artefacts comprising parallel-sided blades, leaf-shaped points and scrapers of Larnian type. Polished stone axes were also found on-site, now occupied by a housing estate. The headland of Howth is linked to the mainland by a low-lying isthmus of beach sand and gravel at Sutton. At the time the midden was in use Howth was an island, and the midden was situated on the old shoreline along the western side of the headland. The boundary wall of Howth Demesne approximately follows this old western shoreline.
A large excavation to house a water tank was opened within the carpark area in Howth opposite St Mary’s. This area had already been tested during the initial assessment for the development. The excavated area measured c. 10m2 by 5.5m deep. It was found the area was reclaimed in the later part of the 20th century during the development of the marina. The first 4–4.5m of excavated material consisted of fill. The fill was homogeneous in texture and consisted of small to very large blocks of granite and gravel. Small circular holes in the larger stones indicated blast quarrying. There was no domestic or builders’ waste material within the fill, with the exception of a number of well-dressed granite blocks: e.g. windowsills, column braces, lintels and other worked objects. These must have been carefully selected as there was no red brick evident. The base material below the infill consisted of layers of gravel and rounded stone.
The north-facing section of the excavation removed a large section of the old sea wall. The wall was composed of large granite blocks at a c. 40° angle. This sea wall can be seen in a number of old photographs and was in use up to the latter half of the 20th century.
For most of its extent along Harbour Road, the pipeline trench was largely along the fault line dividing the old shore deposits, principally sand, and the boulder/gravel infill of the old shoreline.