Nine metres across and just 0.6 metres high, it is easy to dismiss as a natural irregularity in the ground. What it actually represents is something far older and more intriguing: a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, typically dating from the Bronze Age. The mound itself is composed of burnt and fire-cracked stone, the accumulated debris of repeated heating. The usual method involved using these stones to bring water in a nearby trough or pit to the boil, after which food, most likely meat, would be cooked in the heated water. Once a stone cracked from thermal shock it was discarded, and over time those discarded stones built up into the horseshoe-shaped or irregular mounds that survive today.

Fulachtaí fia are among the most common archaeological monuments in Ireland, yet individual examples like this one at Glebe Marsh tend to attract little attention precisely because they are so unassuming. There are no dressed stones, no upstanding walls, no dramatic silhouette against the sky. What remains is essentially a rubbish heap, but a rubbish heap that preserves a remarkably direct record of repeated human activity across what may have been centuries of use. The south-facing aspect of the slope at Glebe Marsh is a detail worth noting; such orientations are common at these sites, possibly reflecting practical choices about drainage or proximity to water sources in low-lying ground. The field fence running north to south across the mound is a reminder of how routinely these monuments have been absorbed into the working agricultural landscape without particular recognition.