There is nothing on the surface to suggest they are there at all. This is a souterrain, an underground stone-lined structure of early medieval Ireland, typically associated with nearby settlement and used variously for storage, refuge, or both. What makes this one quietly arresting is the combination of deliberate concealment, evidence of burning, and the fact that it came to light only by accident, when quarrymen broke into it in 1896.

The discovery was recorded by a researcher named Gillman, who published an account the following year. The souterrain sits within the northern half of a pre-existing earthwork and comprises two chambers joined by a creepway, the low connecting passage that required anyone passing through to crawl. The first chamber is wedge-shaped, roughly eleven feet long and between three and nearly five feet wide, oriented northwest to southeast. Its southeastern end was partially destroyed by the workmen who uncovered it, though one stone lintel was still in place at the time. The creepway leading from that chamber to the second was blocked at both ends, apparently on purpose. The second chamber, running north to south with a curved southern end, was blocked with sand and stone and was never fully explored, so its full extent remains unknown. Both chambers showed blackened walls, and the second contained charcoal, burnt clay, and a flat flagstone that Gillman interpreted as a hearth. A fragment of bone was recovered from the first chamber. Whether the blocking and burning represent deliberate abandonment, a moment of crisis, or something more mundane is not something the physical evidence settles cleanly.