Roundhouse Excavations 2008

In 2008 the Field School excavated a house platform above the Deserted Village. Excavations revealed a substantial, stone built, circular structure thought to date from the Early or Middle Bronze Age.

Roundhouse 1

Roundhouse 1 is one of a pair of circular structures located 50m apart on the 150m contour on the southern slopes of Slievemore Mountain. Prior to investigation the site appeared as a level circular platform, with a slightly dished interior and the top of a circular stone wall visible in places around the perimeter. Whilst the interior seemed a little unimpressive, the view from down slope was more dramatic as the scale of the curving wall was clearly apparent. The structure is built on steeply sloping ground overlooking the valley floor far below, and equidistant between the two structures there is a curvilinear pre-bog field wall running up the mountain, apparently part of a field system that divides the southern side of Slievemore into a series of long strips (Figure 1).

Figure 1

A total of six trenches were excavated across the site and a complicated and monumentally proportioned structure has been revealed (Figure 2). The structure is roughly circular in plan with an external diameter of approximately 11m. It is defined by a substantial stone wall and has an entrance at the south east. The southern arc of the wall is particularly complicated and consists of numerous components (Figure 3). The outer perimeter of the wall is defined by a ring of substantial kerbstones behind which is a large dry stone wall that stands up to 1.7m high and is up to 2.2m wide (Figure 4). The internal edge of the wall is also defined by a second ring of large kerbstones. The top of the wall is wide and level and a vertically sided flat-bottomed trench runs through the middle of it which was 0.5m wide and 0.7m deep where investigated. The slot contained a loose sandy clay fill with some charcoal. The kerbstones, of varying sizes, included some very large boulders. Sections of both the inner and outer rings of kerbstones had fallen away from the wall, but as the wall had not subsequently collapsed it is suspected that the kerbstones were not actively retaining the wall.

Figure 2

Figures 3 & 4

The wall at the north was generally similar in construction, but was shorter and narrower. It again consisted of internal and external rings of kerbstones, but with a rubble core, retained by dry stone facing, rather than the well coursed stone work seen at the south. There is no continuation of the central slot feature around the north of the building. The northern wall is approximately 1.4m wide and stands to a height of 0.8m (Figure 5).

A small exploratory trench was placed over the wall at the west of the structure where there was a suggestion that an entrance may have been located. This trench did not reveal the full width of the wall but showed that the entrance was a secondary feature relating to the use of the structure as an animal pen in the Early Modern period. The slot feature was present at the east of this trench but the wall otherwise had more in common with the smaller northern part of the wall than the larger southern part.

Figures 5 & 6

A trench in the centre of the structure revealed a deep build up of peat within the interior overlying a thin buried turf layer, complete with preserved grass and frequent charcoal. Underneath this turf there was a spread of dark charcoal rich material which covered a hearth, two adjacent postholes and a series of small stakeholes (Figure 6). A series of samples from these features are being processed in order to obtain further radiocarbon dates which should relate directly to the use of the structure.

The structure has a complicated entrance located at the south east (Figure 7). The entrance is an elongated sunken feature with a stone lined base and large stone slabs flanking the sides. 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. A sil stone is present running between the two stones of the outer, eastern pair of orthostats. Interestingly the entrance feature extends into the buildings interior and so the inner pair of orthostats are actually internal features. On either side of the entrance there is a large cairn like mass of rubble retained by large boulders, and the eastern end of the entrance, beyond the pair of orthostats, expands out to join with this material, in a funnel like manner.

A final feature was found abutting the northern side of the north wall and the northern side of the cairn like material to the north of the entrance. This is 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 has subsequently collapsed (Figure 8).

Figures 7 & 8

The artefact assemblage from the structure was severely limited, consisting of 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. No bones, animal or otherwise, were recovered from the site due to the highly acidic nature of the soil. A radiocarbon date of 1411 - 1210 cal BC has been obtained from a piece of charcoal from the preserved turf layer within the structure’s interior, but as this layer has been conclusively demonstrated to post date the collapse of the structure, this date is a terminus ante quem.

The structure is more architecturally complex than could have been imagined prior to the excavations and it is not entirely clear how a timber superstructure could be incorporated into the stone walls. Whilst there are two postholes in the centre of the building, they could not have been used simultaneously, and there is no evidence indicating the presence of an internal post ring closer to the perimeter of the structure, which suggests that the superstructure was supported by a solitary upright post and the top of the dry stone wall. The absence of the slot feature in the northern part of the wall is confusing if this feature was used to tie the roof into the walls. Extended covered entrances are frequently observed at Bronze Age roundhouses, but the entrance to this structure was almost certainly not covered by a roof as no postholes were located along its sides.

Approaching the building from the east a person would have been funnelled between the two horn like projections of stone into the entrance feature proper which was marked by two orthostats and a sil stone. Progress would have been made along the stone lined entrance through the door of the building but instead of opening out immediately, the entrance continued for a short distance and a second, larger pair of orthostats would be passed through before the interior space could be properly accessed. The interior space would be dominated by the central post supporting the roof and the ring of large kerbstones fronting the wall.

The location of the structure so high above the valley floor, the way in which the southern wall was apparently designed to enhance the structures visibility, the small size of the artefact assemblage and the complex nature of the entrance and the horn like projections of cairn material all suggest that the structure was not a standard domestic building. It is possible that this structure and the adjacent building had a special function, such as cult houses, or places in which religious observance were held. Further to the east a group of megalithic tombs occupy a similar position on the mountainside, and it is possible that these structures represent a continuation of ritual activity at the same altitude.

Figure9

The preserved turf layer from which the radiocarbon date was obtained is relevant to this discussion (Figure 9). This turf could not have developed whilst the structure was roofed, and indeed it was found to overlay both the kerbstones and the collapse from the wall, demonstrating its secondary nature. The presence of charcoal throughout this turf layer is therefore thought to represent people visiting the partially collapsed ruins of the structure.  That the site was still visited regularly enough to permeate the turf with charcoal is surely a reflection of its former importance, although the exact nature of this secondary activity has not yet been established. 

During the excavations the possibility that the structure was some form of megalithic tomb, or unroofed circular enclosure was discussed. On balance, these interpretations now seem unlikely but it is worth pointing out that the structure does contain numerous elements that have parallels in the megalithic repertoire. In particular the appearance of the entrance with its pairs of orthostats and the curving projections of cairn like material certainly bears a passing resemblance to some court tombs, passage tombs with in-turned entrances, and even more so the Clyde cairns of Western Scotland, whilst the overall design of a long passage through a circular cairn into an open roofed circular space lined with kerbstones is rather reminiscent of the Clava Cairns of North East Scotland, and to some degree even Fourknocks 1, Co. Meath. It is therefore possible that the builders of this structure were consciously aping megalithic architectural themes. The similarities in design may be entirely coincidental, and at this stage it is not considered prudent to over emphasise these possibilities.

In 2009, the Achill Field School will investigate the adjacent structure and it is hoped that the two excavations will complement each other and provide a better understanding of when these structures were built, what their exact form was and what activities took place within them.  

Copyright 2008 Achill Archaeological Field School.