On its own it might pass for a trick of the terrain, but two smaller depressions nearby, to the south and southwest, suggest something more deliberate lies underneath. The leading interpretation is that this is a collapsed souterrain chamber, the roof of an underground passage having given way and settled into the earth above it.

Souterrains are stone-lined underground passages or chambers built during the early medieval period, typically the first millennium AD, and are commonly found associated with ringforts, the circular enclosed settlements that were the basic unit of rural life in Ireland for centuries. They were used variously for storage, refuge, or both, taking advantage of the stable cool temperature below ground. The ringfort at Skahanagh, recorded separately, provides the broader context here: the souterrain would have served whoever occupied that enclosure, its entrance long since lost and its structure now legible only as a set of faint hollows in the grass.