One slab in the southeast quadrant is more puzzling still. Set on its edge, it bears on its east face a circular depression measuring roughly 35 centimetres across and 15 centimetres deep, carved into the stone with a deliberateness that is hard to ignore and difficult to explain.

The site is known as Ballynahaglish, from the Irish Baile na hEaglaise, meaning townland of the church, which tells you something important: there was once a church here, though what remains of it now is only a site within a subcircular enclosure. That enclosure also contains a souterrain, an underground stone-lined passage typically associated with early medieval settlement in Ireland, used variously for storage, refuge, or purposes that archaeologists continue to debate. The graveyard sits directly north of old Tahilla village and northwest of Coongar Harbour on the Iveragh Peninsula, looking south across Kenmare Bay toward the Beara Peninsula. The layering of the place is considerable: early medieval fabric, post-medieval burial practice, and contemporary use all occupying the same ground at once.

The enigmatic carved depression on the southeast slab resists easy categorisation. Such cup-like hollows appear elsewhere in Irish archaeology in contexts ranging from prehistoric rock art to later ecclesiastical stonework, but what function this particular example served at Ballynahaglish is unknown. It is the kind of detail that rewards a slow walk around the enclosure rather than a glance from the entrance, easily missed among the more conspicuous modern monuments.