It looks, at first, like little more than a stone that has worked its way loose over the centuries. In fact, it is almost certainly a roof lintel, sitting in its original position, marking the buried entrance to a souterrain: an underground stone-built passage or chamber, constructed during the early medieval period and typically used for storage or refuge.

The cashel itself, a type of stone-walled ringfort, contains what the 1930 Ordnance Survey six-inch map labels simply as "Cave" in its western half. That label, cautious and plainly descriptive, turns out to be more accurate than it might appear. Across the interior of the ringfort, the buried structure announces itself in the way these things tend to do: not through visible stonework, but through the ground's reluctance to stay flat. A shallow depression measuring roughly 1.6 metres runs just north of the exposed lintel, and a few metres further north-east, a second depression, around 3 metres long and 0.4 metres deep, yields another flat slab pushing up through the turf. Together, these surface irregularities trace the probable line of the souterrain beneath. In the north-eastern quadrant of the ringfort, a larger grassed-over hollow, between 2 and 4 metres wide and extending for 12 metres on a roughly north-south axis, may represent a collapsed passage or chamber. No stones are visible within it, which suggests the roof has long since given way and the void below has settled.

What makes the site quietly arresting is precisely this combination of the legible and the lost. One lintel remains in place, apparently undisturbed, while elsewhere the ground simply sags where something hollow once held firm. The souterrain has not been excavated, and its full extent remains a matter of surface reading rather than certainty.