Signal Tower — Bunnamohaun

Situated on a low hill at the W of Clare Island (143m OD) with Knockmore Mountain rising to the E. Located in a shallow linear depression that runs N-S across the top of the hill, with a moderate slope to the E and a low rocky cliff to the W. Sited c. 149m NE of coastline at nearest point. The surrounding area consists of unenclosed blanket bog. The Shivel Head Signal Tower has unobstructed views to the N, W and S, but the view to the E is blocked by the mass of Knockmore Mountain. The signal tower at Saddle Hill (MA042-051----), located c. 12.6kms to the N\NNE to the NW side of Achill Island, and the tower on Inishturk Island (MA094-027---), located c. 11.2kms to the SW\SSW, are both clearly visible from Shivel Head in good weather. Site located c. 3.85m WNW of Clare Island Abbey (MA085-013001-), c. 828m W of a group of eight booley huts (MA084-004001- to MA084-004008-) located on the lower SW slopes of Knockmore Mountain, and c. 2kms NW of a coastal promontory fort (MA084-005001-) located on a narrow peninsula at ‘Doon’, Strake. The remains of an early nineteenth-century (c. 1806) originally two-storey square-plan signal tower (int. dims. 4.25m N-S x 4.25m E-W; wall H 5.98m), built with roughly coursed limestone and sandstone rubble stone masonry. The signal tower survives as a partially-collapsed ruin, and consists of the partially infilled semi-basement level, the ground floor level, and with some surviving sections of the first floor level still upstanding. Small shallow segmental-headed window openings are found on the N and S elevations at ground floor level; roughly squared sandstone voussoirs to window arches. The lower portion of a window opening at first floor level is present on the W part of the N wall, with part of the stonework ‘pillar’ that would have separated the two first floor windows also still extant. The lower part of the doorway opening survives to the centre of the W elevation at first floor level. The external face of the E wall is plain. Internally, the ground floor and surviving parts of the first floor walls retain traces of render. The semi-basement level is partially infilled with soil with only the upper section is exposed. Slots for the ground floor joists are present to the N and S walls, below the window openings. The position of the former floor level to the first floor is indicated by a deep slot that runs across the W wall, and a small section of a matching slot is present at the S of the E wall. The ground floor level of the E wall features a central square-headed fireplace with flanking square-headed alcoves to either side. Roughly squared cut stone lintels survive to fireplace (limestone) and to the alcoves (sandstone). A pair of joist holes are located on either side of the base of the fireplace, at the height of the original ground floor. The signal tower is surrounded by a large spread of rubble, which extends for a considerable distance to the E, which indicates that the signal tower collapsed in that direction. The upper part of the signal tower collapsed during strong winds in the winter of 1989\1990 (Gosling et al. 2007, 181). The signal station is set within an almost square enclosure (int. dims. c. 27m N-S x c. 23m E-W) defined around the N, E and S sides by a largely collapsed rubble stone wall. The W side of the enclosure is defined by the exposed rock outcrop along the W side of the depression that runs across the top of the hill. A drystone boundary wall running along the top of the rock outcrop is not related to the signal station, and was likely built for later livestock management. In the SW corner of the enclosure, c. 10m SW of the signal tower, there is the foundations of a large oval-shaped lime kiln (int. dims. c. 4.1m N-S x c. 3.7m E-W; MA084-001003-) with an opening aperture to the S. A low rectangular feature (int. dims. 3.1m E-W x 1.75m N-S) is located approximately 6m W of the signal tower, which may be the rubble stone foundations of a small hut. To the SE corner of the enclosure, adjacent to the S of the above ‘hut’ site, is found the remains\foundations of a small rectangular\oval feature with gently curved corners (int. dims. 4.1m E-W x 2m N-S) defined by a single course of rubble stone. This may be a tent platform related to later camping activities, and it probably significantly post-dates the occupation of the signal tower site. 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). References Compiled by: Stuart Rathbone Uploaded on: 07/07/22