Glash Signal Tower — Tóin Na Holltaí

Situated on level ground towards the SW tip of the Belmullet Peninsula (56m OD). Located within enclosed rough pasture with a modern minor road (post c. 1910) to the N and an earlier road to the E that was likely extant at the time the signal tower was constructed. Site located c. 257m ENE of the coastline at its nearest point. The site has unobstructed views in all directions except to the E where the view is blocked by a low barren hill. The adjacent signal stations, Saddle Hill (MA042-051----), located c. 12.6 kms to the S to the NW side of Achill Island, and at Slievemore Hill (MA010-042----), located c. 20.18 kms to the NNE at the NE corner of the Belmullet Peninsula, are now both now ruinous, and no longer visible from the site. Signal tower located c. 560m SE of a coastal promontory fort (MA024-0130001-) and c. 570m SSW of a stone circle (MA024-014----). An early nineteenth-century (c. 1806) two-storey square-plan signal tower, built with roughly squared and coursed rubble (int. dims. 4.2m N-S x 4.2m E-W; wall H 12.08m). Flush roughly dressed quoins to the corners. The signal tower is the best-preserved example in County Mayo, surviving to its original full height to most elevations. The signal tower is positioned with its elevations facing N, E, S and W. The doorway is located on the first floor of the W wall and would have been originally accessed via a retractable ladder. The original cut stone surround and cut stone threshold\sill has been removed\robbed out. The wall above the doorway has collapsed, removing any trace of a machicolation over. Curved bartizans are located on the NE and SE corners supported by conical stonework. The N and S walls each feature two square-headed window openings at both ground and first floor levels; original cut stone sills now removed\robbed out. The E wall features a wide but shallow bow built within the structure to incorporate the chimney flue. A square chute passes through the base of the E wall towards S edge, and a rectangular chute passes through the base of the E wall towards the N edge, slightly higher up. A complete coursed and roughly squared rubble stone chimneystack is in place to the centre of the E wall. The internal space consists of a partially infilled semi-basement level, a room at ground floor level, and a room at first floor level. This signal tower does not feature a split mezzanine level between the ground floor and the first floor, and it does not feature a low attic level (as seen at other buildings of this type). The flat roof had been accessible from the first floor level. A roughly squared and coursed rubble stone parapet wall protects the edges of the roof, and connects to the bartizans and had originally connected to the now collapsed machicolation. The floors and the roof of the building had been wooden and were carried in the thickness of the wall. No parts of the floors or the roof have survived, but rows of joist-holes indicate their former positions. The E wall had central square-headed fireplaces on the ground floor and first floor rooms, flanked by square-headed alcoves to either side; roughly squared voussoirs to fireplace at first floor level with round-headed relieving arch over with roughly dressed voussoirs. Additional joist holes were located on either side of both fireplaces. The opening of the chute that passes through the S edge of the E wall into the semi-basement level was located 0.8m below the ground floor level. The internal opening of the chute that passes through the N edge of the E wall is not visible. Remains of sections of lime render survive to the interior. The signal tower is located within the E part of a rectangular enclosure (ext. dims c. 55m E-W x 30m N-S), but this is now barely visible above ground. It is marked by sections of largely infilled ditch with occasional discontinuous alignments of stones along its internal edge. Traces of an infilled pit are located 6.5m W of the signal tower. The feature is a circular shaped grass covered depression (diam. c. 2.5m). This feature may be an infilled lime kiln or an infilled socket for a signal mast. 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: 03/02/22 Images: MA024-031----.01 N exterior 1 MA024-031----.02 N exterior 2 MA024-031----.04 NE oblique view, exterior MA024-031----.05 E exterior MA024-031----.06 NE oblique view, exterior MA024-031----.07 NW exterior MA024-031----.08 W exterior 1 MA024-031----.09 W exterior 2 MA024-031----.10 SE oblique view, exterior MA024-031----.11 SW oblique view, exterior MA024-031----.12 S exterior MA010-042----.13 N interior 1 MA024-031----.14 N interior 2 MA024-031----.15 E interior MA024-031----.16 S interior MA024-031----.17 W interior MA024-031----.18 N exterior drawing MA024-031----.19 E exterior drawing MA024-031----.20 S exterior drawing MA024-031----.21 W exterior drawing MA024-031----.22 N interior drawing MA024-031----.23 E interior drawing MA024-031----.24 S interior drawing MA024-031----.25 W interior drawing MA024-031----.26 Plan of site MA024-031----.27 E interior 2 MA024-031----.28 View of enclosure bank to the SW, Looking E MA024-031----.29 View of former mast mount, Looking E