When a V-shaped drain was recently deepened across a gentle south-west-facing slope in Glen, it sliced through something buried roughly forty centimetres below the surface: a thin band of heat-fractured sandstones and charcoal fragments, the remnants of a fulacht fia.

A fulacht fia is a type of prehistoric cooking or industrial site found in great numbers across Ireland, typically consisting of a trough filled with water and heated by dropping fire-cracked stones into it. The stones fracture with repeated heating and cooling, and it is exactly these distinctive fragments, along with the charcoal debris of the fires that heated them, that mark the site in Glen. The exposed deposit is modest, running about 2.1 metres in length and only around 25 centimetres thick within the drain face, yet it is enough to identify the site clearly. What makes the location particularly striking is its context: the drained peat basin in which it sits contains at least six other fulachtaí fia, with the nearest recorded example lying roughly 130 metres to the west-south-west. A steep hill rises close to the south-east, and the whole basin appears to have been a focus of repeated prehistoric use, suggesting this quiet corner of Mayo was once a place where people returned again and again, over generations or even centuries, to work, cook, or gather.