Giants bed — Croaghonagh

In mountainous, blanket bog-covered terrain, located on a natural elevation at the NE end of Lough Mourne. The location provides views towards Barnesmore Gap, an important natural routeway through the Blue Stack Mountains, which lies c. 5km to SE. This cairn is shown on the 1836 and 1906 OS 6-inch map as an oblong feature named ‘Giants Bed’. A cluster of stones (DG086-002002-), shown immediately to SW of the cairn, is named ‘Stones’ on the 1836 edition and ‘Standing stones’ on the 1906 edition. When recorded by the Megalithic Survey of Ireland, the cairn appeared as a long, low, largely peat-covered mound, roughly trapezoidal in plan (25.5m NE-SW; 15m NW−SE at E, c. 8m at W), rising 0.5-1m above the surrounding boggy ground; it was interpreted as the remains of a megalithic tomb of unclassified type (Cody 2002, 63-64, no. 43). The cairn was damaged and partly robbed of stones in the past; Cody (ibid) records that ‘Thomas Fagan's account (1845-8), which includes a rudimentary sketch, describes a large disturbed cairn, at the NE end of which a pit 12 feet by 8 feet (c. 3.65m by 2.4m) and a 'few' feet deep had been dug 'in search of supposed hidden treasure' sometime before his visit there in 1846.’ In advance of the proposed construction of a dam at Lough Mourne, which will raise water levels and partly flood the area, archaeological test trenching took place at the cairn in 2010, and a programme of full excavation (licence no. 10E0309, 10R0103) followed in 2011 (Delaney 2013). Excavation revealed that the cairn consisted of an oval mound (c. 24m x c. 16m) of stones, which covered two small chambers or cists. Despite past disturbance, the cairn survived in parts to a depth of three or four courses. Its construction involved three main phases: a level foundation deposit was laid, incorporating the two cists; the foundation level was then enclosed by a stone bank defining an oval area (c. 15m x 9m), with a number of large stones placed around the base of the bank, probably functioning as a revetment; finally, the oval area was infilled with angular stones to creating the main body of the cairn. The two chambers or cists were built into the foundation deposit, and appeared to be primary features of the cairn. They were located adjacent to each other towards the SW end of the cairn. The more westerly cist (L 1.62m; Wth 1.6m; H 0.7m) was constructed on subsoil at the SW edge of the cairn, and was overlain by the stone bank defining the main body of the cairn. The NW end of this small chamber was defined by three large stones with flat internal faces; the SE end, was partly defined by a setting of smaller overlapping stones, which may have been a later modification; the cist may originally have been intended to be open to E. The floor was covered by dark brown clay, sealed by a layer of uniform small cobbles, extending out of the cist to E. Charcoal from the clay layer was identified as coming from six species, oak, willow, hazel, elm, cherry/blackthorn and birch. A charcoal sample (birch) sent for radiocarbon analysis produced a Neolithic date, 3695-3535 BC (UBA 19992). The second cist (L 2.5m; Wth 25m; H 0.6m), located 1.5m to NE, was subcircular in plan, with an opening to S. It was defined by large stones resting on subsoil, except for the W side, where a natural bedrock outcrop was utilized, and topped with small stones. Silty clay covered the floor, sealed by a deposit of small stones. Neolithic flint artefacts, including scapers, blades and flakes, were recovered from the foundation levels of the cairn, including the cists, from the enclosing stone bank and from the body of the cairn; none appeared to have been deliberately deposited: they may simply have been lost or discarded either by the cairn builders or visitors to the cairn (Delaney 2013, 9-13). Pollen analysis of a dated peat core, sampled from the vicinity of the cairn, suggests that during the Neolithic the location consisted of an exposed upland plateau, with open birch woodland, and alder around the lake shore. Blanket bog began to develop from the mid-Neolithic period onwards, and was most likely widespread by the Bronze Age (Delaney 2013, Appendix 2.4: B. Steffanini). The excavation also uncovered a complex of previously unknown monuments associated with the cairn, demonstrating that this location remained an important focus of activity from the Neolithic period to the late Bronze Age: hearths (DG086-002003-) underlying the foundation layers of the cairn indicate a phase of Neolithic activity at the site predating the construction of the cairn; a wedge tomb (DG086-002004-) was built immediately to SW of the cairn in the early Bronze Age; a pit (DG086-002006-), with associated burning, located immediately to E of the cairn, and a burnt spread (DG086-002005-) 45m to SE, dated to the middle Bronze Age, and in the late Bronze Age, a fulacht fia (DG086-002007-) was built 6m to N of the cairn. The excavator concluded that the cairn may have served as a ceremonial focal point and landmarked on an important prehistoric routeway through the Barnesmore Gap (Delaney 2013, 32). Compiled by: Jane O'Shaughnessy Date of revised upload: 12 January 2018 See linked document with details from Eamon Cody, Survey of the Megalithic Tombs of Ireland. Volume VI. County Donegal. (Dublin: Stationery Office, 2002)