Promontory fort - coastal

The National Monuments Service's description

This site, known as 'Dun Bunnafahy', lies along the SE shore of Achill Island in an area of mountainous bog and sheep grazing. The site is overlooked by high ground to the E and N and is clearly visible from the road known as the 'Atlantic Drive'.

It is situated on the end of a triangular NW-facing promontory and is surrounded by sea rocks and cliffs on all sides. The view from the site is panoramic. This site is marked on the 1920 edition of the OS map and was briefly described by Westropp. The site consists of a well preserved promontory fort defended by a straight bank and a deep ditch. The interior measures 50m long by 28m wide, and is nearly level. It is featureless. Sea rocks which extend out from the top of the promontory suggest the interior may have been larger when the site was fortified. The defensive bank contains a cell-like structure and a causeway crosses the ditch. The bank is well defined and steep sided earth and stone and stands 1m above the level of the interior at the S, rising to 2.3m at the northern cliff edge. It is up to 12m wide at its base and it was topped by a stone wall. This wall is clearly visible for most of its length, and measures 1.85m in width. It is best preserved near the centre S of the cell-like structure where up to five courses of regular schist slabs remain along both the inner and outer faces. The wall and the bank peter out at the southern edge, suggesting that the entrance through the wall was along here.

A modern path runs along the cliff edge at this point. A square cell-like structure measuring 1.26m in width lies within the wall near the centre. It is made of upright slabs standing 0.5m high. This may be part of an entrance feature as it lies opposite the causeway which crosses the ditch. It is not clear whether the cell opened out into the interior or out into the fosse. The ditch is also well preserved, especially towards the N where it is flat based and steep sided. The base is 4.5m wide and lies 6m below the top of the bank and 3m below the outer ground level. The base of the ditch is filled with rubble from the wall, and the remains of a drystone wall that ran along the outer edge of the ditch are still clearly visible. A causeway 5m wide crosses the ditch near the centre and opposite the cell in the wall. Ths sides of the causeway are 1m above the base of the ditch and show traces of having been revetted with stone. The entrance into the interior seems to have consisted of the causeway, a path running along the outer face of the wall towards the southern cliff edge and entering the site through a gap in the bank and wall near the edge. Westropp described two large uprights flanking a possible entrance at the southern end of the bank (1914a 308-9). One slab, now recumbent, remains and the other seems to have slipped into the sea. Also mentioned by Westropp is a circular hut which stood at the entrance the causeway. No trace of this remains. An earthen bank running parallel to the defences 25m to the E are the remains of a later cliff-edge wall.

These descriptions are derived from the MA thesis of Markus Casey 1999 The coastal promontory forts of Ireland. A survey of counties Sligo, Mayo, Galway and Clare. Unpublished MA thesis, National University of Ireland, Galway.

Date of upload: 5 December 2018

References

Westropp, T.J. 1914 The promontory forts and early remains of the islands of Connacht. Journal of the Royal Society of Antiquaries of Ireland 44, 297-337.

Casey, M. 1999 The coastal promontory forts of Ireland. A survey of counties Sligo, Mayo, Galway and Clare. Unpublished MA thesis, National University of Ireland, Galway.