The uncertainty is the point. A cromlech, the older term for what we now generally call a portal tomb or dolmen, typically consists of large upright stones capped by a massive horizontal slab, the whole arrangement representing the burial architecture of prehistoric communities. Whether the structure at Cúil Aodha ever matched that description is genuinely unknown.

The sole early record comes from the Ordnance Survey's six-inch map of 1842, which marks the spot with the label "Cromlech". The accompanying memoranda from the same year are more vivid, describing the object as "a very perfect Cromlech or Druid's Altar", a phrase that suggests something substantial and legible was visible at the time. Yet by the revised six-inch maps of 1903 and 1940, the feature had vanished entirely from the cartographic record. Scholars Ruairí de Valera and Seán Ó Nualláin, cataloguing megalithic monuments across Ireland, noted the site in 1982 but were cautious: the original nature of the feature, they concluded, remains uncertain. It was removed at some point in the intervening decades, and a sports field now occupies the ground where it once stood, or was once thought to stand.

What lingers is the gap between that confident 1842 description and the subsequent silence. Whether the structure was dismantled, robbed for building stone, or had simply been misidentified in the first instance, the record does not say. Cúil Aodha sits in a landscape with genuine prehistoric significance, and the possibility that a "very perfect" monument was lost within a century of being formally noted makes this absence, in its own way, as striking as any surviving stone.