Signal tower

The National Monuments Service's description

Situated close to the summit of a large flat-topped granitic hill (101m OD) known as Cnoc an Choillín. The hill-top setting consists of unenclosed blanket bog with frequent rocky granite outcrops. A large cleft in the hillside is located to the NE of the site running NNW to SSE and provides a convenient access route to the top. Another large cleft in the hillside is located to the SE of the site running NE to SW down to the coastline at Ards Bay, which is the closest point of the coastline to the signal tower site c. 475m to the SW. The signal tower has unobstructed views in all directions, except to the NE towards the summit of Cnoc an Choillín. The well-preserved signal tower on Lettermullan Island (GA089-013----), located c. 12.5 kms to the SE, is clearly visible during good weather. The signal tower at Bunowen Hill (GA049-017002-), located c. 19.9kms to the NW, has been demolished and can no longer be seen from this location. The site of this signal tower at Ard Castle Hill\Cnoc an Choillín is located c. 259m ENE of a holy well (GA076-007), known as ‘Tobar Muire’, located on the W side of Cnoc an Choillín, and c. 1.18kms NW of the Roman Catholic chapel (GA077-006----) located in the village of Carna.

The site of an early nineteenth-century (c. 1805-6) originally two-storey square-plan signal tower (ext. dims. c. 5.8m NW-SE x c. 5.8m NE-SW; max H c. 0.75m to SE elevation). The signal tower has collapsed or been demolished, and most of the masonry has been removed from the site for use elsewhere. Apparently, this signal tower had fallen by 1865 (Robinson 1985, 35). The surviving part of the tower consists of a few courses of roughly squared and coursed rubble granite walling, defining a square-plan building with its walls facing NW, NE, SE and SW. No other architectural details are visible. The most intact portion of the building is at the SE, where the wall survives to H of 0.75m. The base of the signal tower site is surrounded by a spread of rubble (c. 25m NE-SW x c. 15m NW-SE). The rubble spread is not particular dense. Comparison to the more extensive rubble spreads recorded at signal stations such as Cleggan Hill, County Galway (GA009-007----), or Slievemore Hill, County Mayo (MA010-042----) supports the idea that much of the stone from the signal tower has been removed from the site. Short alignments of stone are visible within and adjacent to the rubble spread. These could be fragments of a removed enclosure or fragments of small buildings that had surrounded the signal tower. These alignments are too obscured to sufficiently interpret onsite.

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).

Compiled by: Stuart Rathbone

Uploaded on: 11/07/22

Images:
GA076-006----.01 SE exterior
GA076-006----.02 NE exterior
GA076-006----.03 NW exterior
GA076-006----.04 SW exterior
GA076-006----.05 SE interior
GA076-006----.06 SW interior
GA009-007----.07 Site plan
GA009-007----.08 Fragment of wall to N of site of signal tower, looking E
GA076-006----.09 View of wall to N of site
GA076-006----.10 View of wall to N of site
GA076-006----.11 L-shaped wall to S of signal tower site

References

Kerrigan P.M. 1995 Castles and fortifications in Ireland 1485-1945. Cork. The Collins Press.

Robinson, T. 1985 Mapping South Connemara, parts 1-29, Cashal, Carna, Cill Chiarain. Roundstone.

Rathbone, S. 2020. ‘The Construction, Survival and use of Signal Defensible Guard Houses in Connacht and Ulster’; unpublished PhD Thesis, Institute of Technology, Sligo