It may be the wall of a souterrain, an underground stone-lined passage or chamber built during the early medieval period, typically used for storage, refuge, or concealment. What makes this particular feature quietly compelling is that no one has confirmed what it is. Tradition says there is one here; the stonework suggests something is here; but the two have never been formally joined.

The site sits within a cliff-edge fort, a type of enclosure that uses the natural defence of a coastal or elevated precipice as one of its boundaries, supplementing it with constructed walls or banks on the landward sides. Local tradition recorded in the Ordnance Survey Name Books noted the presence of a souterrain within the enclosure, a detail that was written down but never, it seems, followed up with any ground investigation. The exposed drystone wall visible in the cliff section may be part of that same structure, brought to light not by deliberate archaeological work but by erosion gradually undercutting the fort's outer edge.