The depression stretches roughly fourteen metres in length and sits about half a metre below the surrounding ground level, running from the centre of an ancient ringfort out toward the north-east section of its enclosing bank. It is understated to the point of near-invisibility, and that is precisely what makes it interesting.

The site sits within a ringfort, one of the thousands of roughly circular enclosed settlements built across Ireland from the early medieval period onward, typically between the sixth and tenth centuries. These enclosures were generally used as farmsteads, their earthen banks providing a degree of protection for people and livestock. This particular example, recorded under the reference WM023-030, occupies the crest of a hill in pasture land, with open views in every direction. The linear depression running through its eastern sector is thought to represent the collapsed roof of a souterrain, an underground passage or chamber of dry-stone construction that was frequently built within or beneath ringforts. Souterrains served a range of functions, including storage, refuge, and ventilation, and their roofs, typically formed from large flat stones laid across the top, are vulnerable to collapse over centuries of settlement and agricultural pressure. When a roof gives way, the ground above sinks, leaving exactly the kind of elongated hollow visible here. At four metres wide and running the full distance from the interior to the bank edge, this depression follows the profile one might expect from such a structure, though the passage itself remains unexcavated and unconfirmed.