What was lost was almost certainly a fulacht fiadh, the term used for a type of ancient cooking or heating site found widely across Ireland, typically consisting of a horseshoe-shaped mound of burnt and shattered stone accumulated around a water-filled trough. The stones would be heated in a fire and dropped into the trough to bring the water to a boil, and over repeated use the cracked, discarded stones built up into the characteristic mound that survives, sometimes for millennia, in low-lying or boggy ground.

This particular site sat roughly 30 metres north of a related fulacht fiadh already recorded in the area, and around 20 metres from the stream, in ground the surveyor described as waterlogged, exactly the kind of damp, marginal terrain these sites favour. According to the landowner, it matched its neighbour in footprint, measuring approximately 8 metres by 11 metres, but rose to a greater height, suggesting it had seen considerable and repeated use. By the time Michael Connolly surveyed the Lee Valley area in 1996 and 1997, the mound itself was gone, but burnt and shattered stone remained visible at the surface, a faint material trace of something that had otherwise been erased.