Megalithic tomb in An Tonn Bhán

This monument, not marked on any edition of the OS 6-inch map, first came to notice in 1994. It is 700m SSE of Tramore Bay and 700m E of Ballyhoorisky, at the N end of the Fanad peninsula. It stands on a slight ridge immediately W of a long shallow valley. The area provides fair pasture on uneven ground broken by outcropping rock and scattered erratics. There is a good outlook from the site, with the sea visible to the N. An unroofed chamber, open to the NW, survives here. It is c. 4m long and 1.5-1.7m wide. The structure is incorporated in a modern stone field wall, much of which is overgrown by bushes. This wall joins the E side of the front and the W side of the back of the chamber. There is no reliable trace of cairn at the site. A number of displaced slabs in the chamber, not shown on the plan, may have formed part of the structure. There is some evidence that there was a second chamber behind the extant one. Two tall longitudinally set stones, 0.75m apart, mark the entrance to the chamber, immediately in front of which is a natural dip in ground level. Each entrance stone is partly overlapped by a large sidestone. Behind the large eastern sidestone is a much smaller one. A slightly gable-topped stone stands at the back of the chamber and crosses approximately half its width. Behind this the top of a largely buried stone seems to continue the line of the W side of the structure. This stone, 0.2m thick and at least 1.75m long, is exposed to a maximum height of 0.15m at its southern end, and its opposite end is buried. Further investigation would be required to determine its status. Opposite it is another largely buried slab, almost certainly prostrate, c. 2.3m by 0.85m by 0.25m thick. The western entrance stone is 1.5m high. The top of this stone dips toward the back of the chamber. The eastern stone is 1.4m high. The top of this stone also dips toward the back of the chamber. The large sidestone at the E, though free standing, leans inward slightly. It measures 1.2m in maximum height. It reaches this height at mid-length, from where it falls gradually in both directions to 0.3m at the N and to present ground level at the S. A gap, 0.4m wide, between the front of this sidestone and the adjacent entrance stone is largely filled by a stone set on end. This stone is 1.05m high. The smaller sidestone on this side is 0.5m high. The sidestone at the W side of the chamber is 1.3m high measured at its outer face, where its base is partly exposed. The upper part of the sidestone overlaps the entrance stone by c. 0.3m but does not touch it. The transversely set stone at the back of the chamber now leans to the E. This stone appears to be more akin to a segmenting jamb than a backstone. It is 0.8m in leaning height at its inner face. A hole, 0.5m deep, has been dug at the outer face of this stone. Two stones (not on plan) lying in the hole, one wedged against the base of the set stone, appear to be of recent origin. Two displaced slabs (not on plan) protrude from grass-grown fill in the chamber, the outline of which is indicated by a pecked line on the sectional drawing. One of these leans against the inner end of the western sidestone. It measures c. 1.2m by 0.8m by 0.2m thick. The other is beside the eastern entrance stone; it extends into the chamber and, like the other, leans westward. It measures 1.9m by 1m by 0.2m thick. Beside this slab and in front of the first one are at least three smaller slabs and other lesser stones. The monument cannot reliably be classified, but the design suggests some affinity with both court tombs and portal tombs. The two tall longitudinally set entrance stones, each partly overlapped by a large sidestone, are characteristic of the portal tomb, although such an arrangement can occur in court tombs. The indications of further gallery structure, represented by what may be a segmenting jamb and beyond it a possible sidestone, if verified would point to it being the remains of a court tomb. RMP 1995, 8:23. The above description was published in the 'Survey of the Megalithic Tombs of Ireland. Volume VI, County Donegal.' Compiled by: Eamon Cody (Dublin: Stationery Office, 2002). Date of upload: 22 September 2008