Glenhead Tower

Situated on a raised plateau (69m OD) with tall vertical cliffs to the W and c. 550 NE of the W end of the valley where the village of Glencolumbkille is located. Located on flat ground to the SW end of the Sliabh Liag sea cliffs. Site located c. 160m to the SE of the nearest point of the coastline. The surrounding area is composed of unenclosed blanket bog. The signal tower has unobstructed views in all directions. It was originally built to be intervisible with the signal tower at Dawros Head (DG064A001----), now collapsed, which is located c. 12.6kms to the NE and is no longer visible from this site; and the tower at Malin Beg (DG089-034----), which is located c. 7.6kms to the SSW, and which is visible in clear weather. Site located c. 1.2kms NNW of the remains of an early ecclesiastic site (enclosure: DG080-003001-\church: DG080-003002-) associated with St. Columbkille. Site originally accessed by a long laneway from the SE that is now overgrown. An early-nineteenth century two-storey square-plan signal tower with slight base batter, built with roughly coursed rubble sandstone (ext. dims. 5.85m NW-SE x 5.85m NE-SW; H 11.87m). Sections of roughcast lime render survive to the exterior, mainly to the ground floor level. The well-preserved signal tower has survived to its full height, apart from the top of the NW wall and the upper parts of the machicolation over the first floor doorway, which have collapsed (possibly due to lightning strike). The tower is positioned with the walls facing NE, SE, SW and NW. The NW wall features a first-floor doorway that would have been originally accessed via a retractable ladder. This doorway retains its original cut limestone block-and-start surround with projecting keystone to the lintel. The doorway was protected by a now collapsed machicolation, of which little survives beyond the three cut stone corbels that had supported it. The NE and SW walls feature pairs of square-headed window openings at the ground and first floors. The first floor openings retain cut limestone block-and-start surrounds and stone sills; three of the ground floor window openings retain cut stone surrounds and stone sills. SE wall features a shallow outwards bulge that houses the chimney flue. The E and S corners of the tower are protected by intact bartizans, each supported by three cut stone corbels. A parapet wall runs around the top of the signal tower, connecting to the intact bartizans and would have originally continued around the collapsed machicolation above the doorway. Most sections of the original cut stone coping survive to the parapet wall. There is no ground floor access to the interior of this signal tower, and the internal arrangements have not been assessed. The foundations of two small buildings are located close to the cliff edge to the N of the signal tower. It is not clear if these were occupied at the same time as the signal tower, or if these pre-date or post-date the use of the signal tower. The rectangular-plan hut site (4.85m SW-NE x 4.1m NW-SE) to the NW of tower consists of low grassed-over rubble stone foundations surrounded by stone rubble. The rectangular-plan hut site (3.2m SW-NE x 4.1m NW-SE.) to the NE, located 1.2m E of the other hut site, also consists of low grassed-over rubble stone foundations surrounded by stone rubble. A small structure is located immediately NE of the NE hut site. This feature consists of a small circular (int. diam. c. 1.2) grassed-over mound comprised of rubble stone; this may be a lime kiln associated with the construction of the signal tower. The signal tower was part of a system of over 80 signal stations constructed by the British Board of Ordnance in the first decade of the 19th century to warn of the approach of a French invasion fleet. Signalling between sites was accomplished using a naval signal post. The system formed a continuous chain from Dublin Bay running clockwise all the way around the coast to Malin Head in County Donegal. It was abandoned by the mid-1810s when the threat of a French invasion diminished (Kerrigan 1995, 157-66).