Achill Island 2017: Cromlech Tumulus Report 2
February 28, 2018
During July and August 2017 Achill Archaeological Field School carried out a fourth and final season at the Cromlech Tumulus (MA042-021002) and the Danish Ditch pre-bog field wall (MA042-021003), on Slievemore mountain, Keel East townland, Achill Island. The first three seasons at the site were directed by Stuart Rathbone, and the fourth season by Dr. Eve Campbell.
During 2016 work a large 10m by 5.5m trench (Quadrant 5) orientated north-south was excavated over the eastern side of the site. This trench could not be fully excavated due to time constrains and so the picture that emerged was necessarily partial. At its uppermost levels the trench contained a small post-medieval clochán or corbelled stone hut (2.8m east-west by 2.4m). Rathbone identified part of the walls of the Middle Bronze Age (MBA) building in the north-east corner of the trench, and a feature that he termed an ‘entrance passage’ curving for 5m along the northern edge of the cutting. To the east of the trench he found part of a stone wall forming a ‘small circular building built against the southern side of the entrance of the Middle Bronze Age building’. Finally, he uncovered part of a pre-bog field wall coming into the middle of the trench from the east. After the excavation was finished the trench was covered in terram and the sod was replaced.
In 2017 Quadrant 5 was reopened in a bid to fully resolve the area. Work began by excavating the overlying layer of soil and stone rubble concealing the structural remains. Once this was removed the curving eastern wall of the MBA structure became visible along the western side of the trench. The wall was composed of a bank of earth and stone. It soon became apparent that what Rathbone had identified as the MBA building’s ‘entrance passage’ and the ‘small circular building’ were both structural elements of a stone-lined fulacht fia. The feature comprised a stone-lined trough orientated north-west/south-east and measuring 1.8m long by c. 1m wide and 0.45m deep. It was built in the corner between the junction of the eastern wall of the MBA building and the pre-bog field wall, and thus post-dates both features. A stone ledge or platform flanked the southern side of the trough and the entire feature was surrounded by a low stone wall/kerb of variable height. This wall or kerb served as a revetment for the burnt mound that formed part of the fulacht fia. The mound arced around the trough and was most pronounced on its northern and eastern sides. To the south the burnt mound respected the earlier pre-bog field wall. It comprised a deposit of heat-shattered and degraded stone mixed with charcoal and silty sediment up to 0.5m deep. Significant quantities of water-rolled beach cobbles were present in the deposit; most of these were pink sandstone ultimately derived from the Corraun Peninsula. No bone was found in the burnt mound, but a deposit of ceramics thought to represent a single coarse Bronze Age vessel was found in the deposit to the north of the trough. After the final use of the fulacht fia it was deliberately filled in with large stones and the trough was paved with rough slabs to create a level surface. A large sherd of coarse prehistoric pottery found above this layer indicates that this ‘closing’ of the monument occurred in antiquity.
A sondage through the burnt mound in the north-east corner of the trench showed that it overlay a layer containing dense concentrations of worked chert, flint and quartz, with occasional sherds of prehistoric pottery, and moderate concentrations of charcoal. This layer was found to extend along the entire eastern edge of the trench at its lowest levels. A line of four stake-holes were associated with this layer in the southern half of the trench. The dense concentration of lithics, including chips of debitage and partially worked beach-rolled flints suggest that this may constitute a knapping area. A small chert leaf-shaped arrow head and a chert hollow scraper retrieved from this layer suggest a Neolithic date.
Other notable finds from the 2017 season include a stone spindle whorl recovered from the upper layers in the southern half of the site.
The 'Danish Ditch'
During the last two weeks of the excavation a 12m by 2m trench was excavated across the path of the ‘Danish Ditch’, the pre-bog field wall running between the MBA building and a nearby Neolithic court tomb. This was the fourth slot trench excavated over the features since we began our project here in 2014. Previous work has tracked the path of the monument and our 2016 trench was especially significant, revealing that the feature comprises a pair of parallel banks. Our 2017 trench was empty, despite being carefully lined up with the known line of the monument. While analysis is ongoing it seems that it may have been robbed out in antiquity–perhaps related to the construction of the fulacht fia.