As peat is stripped away from bogland across Ireland, it regularly uncovers the traces of an older landscape beneath, one that had been quietly preserved by waterlogged, acidic conditions for centuries. At Derrymihin on the Beara Peninsula in County Cork, that process has brought to light a set of stone field boundaries that were once swallowed entirely by bog, running in a roughly north-south direction across the rough hill pasture, with Berehaven Harbour and Bere Island visible in the distance beyond.

The boundaries, which survive to a thickness of around half a metre and a height of roughly 0.4 metres, extend across an area of approximately 120 metres north to south and 30 metres east to west, sitting on either side of a cairn. A cairn, in this context, is a deliberate heap or mound of stones, often associated with burial or ritual use in prehistoric periods, though cairns were also used as boundary markers. The pairing of field walls with a cairn suggests this was a managed agricultural landscape at some point in the past, though precisely when is not recorded. One detail that stands out is the construction method: many of the stones are set at right angles to the line of the wall rather than laid flat along it, a technique sometimes described as orthostatic walling, which lends the structure a distinctive, almost herringbone quality when viewed from above. The whole arrangement points to a community that organised land carefully, dividing and working ground that is now too rough and wet to farm in any conventional sense.