Man-made underground passage in Doonbeakin

Located on gently elevated ground in the SW quadrant of the enclosure (SL018-095001-), on a strip of land flanked at W by the Ballyglass River and at E by the Doonbeakin River. The Man-made underground passage is of drystone construction with lintel roofing. A rectangular surface depression encloses an access hole (1.6m NE–SW; 0.65m NW–SE) through the roof of the Man-made underground passage, created by the displacement of a stone roof lintel. It opens onto the SE end of a roughly oval chamber (3.62m NW–SE; 1.8m NE–SW; H c. 1.36m). The floor of the chamber slopes down gently towards the NW, and is covered in loose stone rubble. At the N corner of the NW end of the chamber, the two side walls converge at an opening (Wth 0.6m NE–SW; H c. 0.96m) to a short blind passage (L 1.66m NW–SE) which curves slightly to NW. There is no obvious evidence for a continuation of the Man-made underground passage to NW or N from this passage. At the SE end of the oval chamber, the two side walls converge at an opening into a cupboard-like recess or small chamber (L 1.07m NE–SW; Wth 0.75m NW–SE at entrance, expanding to 1.18m at back wall; H 0.76m) which is trapezoidal in plan. It has space sufficient only for one person to crouch in. A large flat slab serves as a threshold stone at the entrance, and is set higher than the floor of the oval chamber. The floor of the little chamber is paved with slabs. The roof is formed by stone lintels. These are arranged so that there is one central, recessed square lintel (0.59m NW–SE; 0.46-0.59m NE–SW). This may be an original trapdoor entrance to the Man-made underground passage, dropping from ground surface into the small trapezoidal chamber which served as an antechamber to the large oval chamber. Beneath the threshold stone of the antechamber is a partly concealed opening into a creep or low, narrow passage (Wth c. 0.75m). The passage slopes down beneath the small chamber/antechamber, the threshold stone of which serves as the first roof lintel of the passage. It is filled with stone rubble but can be seen to continue for at least 2m to SE. There is a field clearance cairn (3m N–S; 3.5m E–W; H 0.8m) immediately to E of the access hole to the Man-made underground passage, and a second field clearance cairn (diam. 4m; H 1.1m) is located 3m to E of that. A bank/scarp, with a pronounced external face (H 0.85m) and a slight internal lip (Wth c. 2m), skirts the two cairns and the Man-made underground passage at S–W, defining the elevated ground on which they are located.