Low, crescent-shaped heaps of fire-cracked stone and charcoal-blackened earth, they are thought to represent prehistoric cooking or processing sites where stones were heated in fire and then dropped into water-filled troughs to bring the liquid to a boil. The example beside the Geestaun River in Ballinamore, County Mayo, is a modest but well-preserved specimen: a sod-covered, semi-circular rise measuring roughly thirteen metres along its longer axis and just thirty centimetres in height, its straight edge running flush against the western bank of the river.

What gives this particular mound its character is the way it sits within a quietly layered piece of ground. The river here is relatively shallow, and the mound's position may reflect proximity to a fording point, the kind of crossing that would have made a spot both practical and frequented across many generations. A ruined stone wall follows the river bank and merges into the straight eastern edge of the mound before curving around its south-western arc, suggesting later use of the same ground long after the mound's original purpose had been forgotten. A grove of trees, recorded as River Wood on the 1919 Ordnance Survey six-inch map, lies immediately to the south, bordering the water. Within a few hundred metres, two further ancient features sit in the surrounding pasture: a rath, which is a circular earthen ringfort of the early medieval period, about two hundred metres to the south-south-west, and an enclosure of uncertain date roughly three hundred metres to the south-west. Whether these features were ever connected in any meaningful way is unknown, but their proximity gives the impression of a stretch of land that was, across a very long span of time, repeatedly chosen rather than merely stumbled upon.