It is easy to walk past without a second thought, but the shape and setting are deliberate, and ancient. This is a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, typically Bronze Age in origin. The characteristic mound is formed from the debris of repeated use, primarily fire-cracked stone that was heated and dropped into a water-filled trough to bring it to a boil. The horseshoe or crescentic form, open to one side, is the telltale signature of the type.

This particular example measures roughly nine metres north to south and four and a half metres east to west, rising between one and two metres in height. Its position is specific and purposeful: close to running water, on sloped ground above the river, with a small stream immediately to the west. The location in Cartrún An Phóna places it within a valley that contains at least two other recorded monuments, suggesting this stretch of Gleann Glaise saw sustained activity during prehistory rather than isolated, incidental use. The details here come from Paul Gosling's Archaeological Inventory of County Galway, published in 1993, which catalogued this and many similar sites across the west of the county.