In a hollow on an east-facing slope somewhere along the townland boundary between Aghnahoo and Corlea in County Leitrim, a small ruined structure was noted in the 1940s: the base of a drystone wall, no mortar, just stones laid against one another, enclosing a footprint of roughly five metres by four. That is a modest space, barely enough for a single room. By the time anyone returned to look properly, in 1992, the heather had won. No visible trace of the monument could be found, and its exact location remains unknown.

Drystone construction of this kind, common across the west and northwest of Ireland, leaves a fragile mark on the landscape. Without mortar to bind them, walls depend on their own weight and the precision of their arrangement, and once that arrangement begins to fail, the stones simply settle back into the ground. A hollow on a slope, filled with decades of heather growth, can absorb a low wall remarkably quickly. What the 1940s record preserves is not quite a building so much as the memory of one: a set of external dimensions, a note about its position on a boundary line, and the implication that even then it was already a ruin.