Roundhouse 1 Summary

Bronze Age Roundhouse on Slievemore Mountain

Roundhouse 1 summary

The prehistoric landscape preserved under the blanket bog on Slievemore represents a large multi-period archaeological complex, and consists of a huge system of pre-bog fieldwalls, a number of Megalithic Tombs, several large roundhouses and numerous smaller sites that are difficult to assess without excavation. The first archaeological excavations of this landscape were undertaken by Achill Field School between 2006 and 2008 at the site of a large well preserved roundhouse, now known as Roundhouse 1.

Roundhouse 1 is one of a pair of large circular buildings set about 50m apart on the 150m contour on the south western slope of Slievemore. The building is set within the massive pre-bog field system and is apparently fully contemporary with the neighbouring Roundhouse 2.

A total of six trenches were excavated across the site revealing a complicated and monumentally proportioned structure. The structure is slightly oval shaped in plan with a maximum external length of approximately 11m and a maximum internal length of approximately 7m. It is defined by a substantial stone wall and has an entrance passage at the south east.

The building is defined by a massive wall that was visible before the excavations but its true scale only became apparent during the excavations. The wall stands up to 1.7m high and is up to 2.2m wide. It is constructed of neat courses of dry stone work, has near vertical wall faces and rings of large boulders form kerbs around the base of both the internal and external faces. Where investigated at the south and west an unusual slot was found to run through the centre of the wall, but this is not present at the north. This slot has vertical sides and a flat base and is up to 0.5m wide and 0.7m deep and is filled with a loose sandy clay fill with occasional pieces of charcoal. At the west of the building a small trench was excavated over what appeared to be a second entrance, but this was found to have been a secondary feature relating to the remodelling of the ruined structure for use as an animal pen in more recent times. A very slight secondary wall was found to overlie the wall around the southern side of the building which also relates to this remodelling.

The building has a very impressive entrance located at the south east. This consists of a long passage through the walls that is lined with upright stone slabs and contained two layers of rough paving. A pair of pillar like orthostats is present at each end of the entrance, with the western, inner pair being slightly taller than the eastern, outer pair. The threshold of the building is marked by a sil stone that runs between the two stones of the outer, eastern pair of orthostats. Interestingly the entrance passage extends beyond the inner edge of the wall into the buildings interior so the inner, western, pair of orthostats actually stand within the internal area of the building.

To the north and south of the eastern end of the entrance passage there are two large cairn like masses of rubble retained by large boulders. The entrance passage opens out to meet these rubble masses in a funnel like arrangement. These features are now suspected to be the ends of pre-bog field walls that connect to the perimeter of the building on either side of the entrance, but this suggestion will need to be checked by further excavation and probing of the bog.

A final rather confusing feature was found abutting the northern side of the north wall and the north western side of the possible field wall to the north of the entrance. It consists of a low platform of densely packed rubble measuring 1.2m in width and at least 2m in length which is retained by a large stone slab. The top surface of the rubble is quite level, and it is believed that originally this feature extended further to the east and west but had subsequently collapsed or been removed

A trench in the centre of the structure revealed a deep build up of peat within the interior overlying a thin layer of buried turf, complete with preserved grass and very frequent charcoal. The presence of so much charcoal in this layer of turf which clearly developed after the building had begun to collapse is very interesting, and suggests that the roofless ruins of the building were visited and fires were lit inside it. These fires seem to have halted as soon as peat began to form inside the building and it therefore seems likely this secondary activity was occurring soon after the building was abandoned. Underneath the buried turf there was a spread of dark charcoal rich material which covered a hearth, two adjacent postholes and a series of small stakeholes; clearly internal features relating to the occupation of the building. The hearth was rather large and could only be partially excavated. Environmental samples from the hearth were interesting because six different deciduous tree species were identified, indicating a healthy woodland was probably present near by. A radiocarbon date of approximately 1400 - 1200 BC has been obtained from a piece of charcoal from the preserved turf layer within the structure’s interior, and a radiocarbon date of approximately 1300 – 1100 BC has been obtained from a sample from the hearth found underneath the buried turf. These initially confusing dates seem to indicate that the hearth was last used sometime after 1300 BC and that the building was abandoned and the turf had begun to form by 1200 BC. The building can therefore be confidently identified as dating from the Middle Bronze Age.

The recognisable artefact assemblage from the structure as a whole was severely limited, consisting of only a fragment of a flint plano-convex knife, a small flint scraper, a fragment of a chert blade and a few pieces of flint debitage. However a large quantity of pieces of smashed quartz were recovered from the site and preliminary analysis of these has confirmed they are not simply natural pieces of quartz but have been deliberately altered. Quartz has been shown to be useful to make implements for a wide range of purposes, but unfortunately it does not lend itself to the creation of easily identifiable tools in the same way as flint or chert. The ongoing analysis of the quartz material from this site, and from others excavated by Achill Field School, promises to provide a great deal of information about how this poorly understood material was utilised in prehistory. No bones, animal or otherwise, were recovered from the site due to the highly acidic nature of the soil.

The excavations at Roundhouse 1 allowed Achill Field School to examine one of the best preserved Bronze Age structures in Ireland. The excavations posed many questions about the nature of the building, how it was roofed, and how it was used. These questions fed directly into the design of the excavations that subsequently took place at the adjacent Roundhouse 2, and taken together these two excavations provide a remarkable glimpse into Bronze Age lives in the west of Ireland.