This is a fulacht fia, a type of site found in considerable numbers across Ireland, typically associated with Bronze Age activity. The term refers to a mound of burnt and shattered stone, the accumulated debris from repeated cycles of heating rocks and dropping them into a water-filled trough to bring it to the boil. The purposes served by this process have been debated at length, with cooking, brewing, bathing, and textile preparation all proposed at various points. What survives at Garrigane is modest but characteristic: an oval mound measuring roughly 5.4 metres north to south and 4 metres east to west, rising only about 38 centimetres above the surrounding ground.

The site was recorded by Bowman in 1934, and his note carries a small detail that adds a layer of history beyond the prehistoric. He observed that the stones which would normally be visible on the surface of such a mound had already been removed by that point. The blackened, fire-cracked stones that form the bulk of a fulacht fia are exactly the kind of loose, ready-to-hand material that gets quietly appropriated for field walls, drainage work, or building over generations, and their absence here likely reflects nothing more dramatic than ordinary agricultural practicality across the intervening centuries. Without the burnt stones present on the surface, the mound reads now simply as a dark earthen rise in wet ground, the characteristic discolouration of the soil itself the main visible trace of whatever activity once took place here.