Though the site had no known historical associations, the earth yielded this hidden chamber system that had likely remained undisturbed for centuries. The discovery prompted an immediate investigation by the Office of Public Works staff, though unfortunately the construction work had already caused considerable damage to the structure.

The souterrain consisted of two chambers positioned at right angles to each other, connected by what archaeologists call a ‘creepway’; a deliberately narrow passage that would have forced anyone moving between the chambers to crawl. The first chamber ran roughly north to south, measuring 4.3 metres long, about a metre wide, and reaching a maximum height of 1.4 metres. From its southwestern corner, the creepway extended for 1.4 metres, with a width of just 47 centimetres and a claustrophobic height of only half a metre. This led into the second chamber, which ran east to west for 3 metres, varying in width from 40 centimetres to a metre.

Among the stones forming the structure’s walls, archaeologists found a fragment of a quernstone wedged near the western end of the second chamber. Quernstones, used for grinding grain, offer a tantalising hint at the souterrain’s possible use or the daily life of those who built it. These underground structures, found throughout Ireland but particularly common in certain regions, continue to puzzle archaeologists; they may have served as storage spaces, refuges during raids, or held some ritual significance we can only guess at today.