A low hollow near a stream conceals what appears to be a souterrain, the term given to the dry-stone underground passages, typically early medieval in origin, that were built across Ireland for storage or refuge. The anomaly here is the scale. When test trenches were dug in 2007, the passages uncovered were just 0.6 metres wide and 0.6 metres high, far too confined for a person to move through with any ease. Whatever was stored or sheltered here, it was not people.

The site has a layered history of investigation. A field inspection in 1989 first brought attention to the feature, noting a large capstone surrounded by smaller stones in the hollow, with the passage apparently running on a northwest to southeast alignment but entirely inaccessible at the time. Nearly two decades later, excavation carried out under licence ahead of a proposed housing development reached the structure at a depth of 1.8 metres below the present ground surface. What the diggers found were two subterranean passages with walls of boulder and sandstone, topped with well-laid flat capstones, built in a manner consistent with souterrain construction but on an unusually diminutive scale. The researchers who examined the site raised the possibility that these passages were not early medieval at all, but were instead connected with a 19th-century mill that once stood nearby. A mill would have had practical reasons for underground chambers, whether for controlling water flow, storing grain in cool conditions, or housing millwork below ground level. The question of which explanation fits better remains unresolved.