Man-made underground passage in Lisnenan

During the course of preparatory soil-stripping to facilitate the construction of an apartment block at a proposed apartment complex and housing development at Lisnenan, Letterkenny, Co. Donegal, the client’s contractor uncovered a possible Man-made underground passage. No archaeological condition applied to the development, which is 60m to the west of a cashel (DG053–015----) and 370m NNE of a holy well (DG053–017----). The client contacted the DEHLG and reported the discovery. Upon consultation with the NMI and DEHLG, and in consideration of the advanced stage of construction, it was recommended that the Man-made underground passage be preserved by record. The excavation was carried out by Declan Moore of Moore Archaeological & Environmental Services Ltd under licence No. 06E0945 in September 2006. The site had been significantly disturbed. No archaeological material other than the Man-made underground passage was encountered. The site is located on a west-facing slope in pasture with occasional rock outcrops and presented as a topsoil-stripped, scarped-out area. A platform upon which the site was located had been left in situ. Little remained in the area of the Man-made underground passage. Much of the overlying material had been removed. Only the stone-lined walls remained in situ. A number of flat stones (possible capstones or lintels) lay in the general area. No capstones remained in situ. The possible entrance was located at the western end (equating to the lower end of the original slope). A section face at the northern limit of the development site (25m north of the Man-made underground passage) provided a base point/indication of the original levels and topography. This indicated a gentle east–west gradient. The entrance area appeared to be a roughly rectangular pit at the western end of the Man-made underground passage. There were a number of large rounded stones at the base. Due to disturbance, it was difficult to discern for certain the nature of the entrance. It was roughly here that the client’s representatives had uncovered the Man-made underground passage when a tractor collapsed. The cut for the Man-made underground passage measured c. 5m in length and curved from east to west. It was filled by the stone walling. At the eastern end an extension to the cut, beyond the area which was walled, was excavated. It was roughly rounded in shape and narrowed to the west at the possible entrance. The corners at the east were roughly rounded in shape. The break of slope throughout was rounded and sharp in parts. The sides were generally vertical and there was a sharp break of slope at the base throughout. The base of the cut was relatively level. The cut for the entranceway was contemporary with the cut for the Man-made underground passage and was roughly rectangular in shape, forming a court shape at the western end of the Man-made underground passage. The break of slope was rounded with a sharp slope and rounded break of slope at the base. Collapsed stones were evident at the base. These may have formed some sort of path, although it is not possible to say for certain whether they were in their original location, as this area had been significantly disturbed. The stone walling of the Man-made underground passage was single skinned. It survived on both sides to roughly nine courses. The stones varied in size, measuring from 100mm by 100mm to 400mm by 500mm. There were occasional slates and some daub in places. The maximum depth of the walling was 1.45m. The first two to three courses comprised smaller stones, with the basal layers comprising much larger stones (Bennett 2009, 98-9). Compiled by Caimin O'Brien Date of upload/revision: 14 November 2011