During test trenching in 2003, archaeologists identified the remains of a burnt mound at the edge of a peat bog at Cahircalla More, close enough to the surface that it had barely been buried. The following year, a full excavation revealed not one but seven discrete prehistoric burnt mounds in the area.

Burnt mounds are among the more intriguing and widespread features of the Irish prehistoric landscape. They are typically low, kidney-shaped spreads of fire-cracked stone and charcoal-stained earth, thought to be the accumulated debris from repeatedly heating stones and plunging them into water-filled pits or troughs, possibly for cooking, bathing, or industrial processes. The particular spread recorded here, one of the seven identified across the site, measured roughly 11.2 metres by 6.7 metres and was only about 0.1 metres thick, lying just beneath 0.3 metres of peat. A radiocarbon date placed its use somewhere between 2330 and 2130 Cal BC, which puts it in the Early Bronze Age, a period when this kind of fulacht fiadh activity was at its most widespread across Ireland. The peat that sealed it had effectively acted as a preserving lid for more than four thousand years, keeping the deposit intact until the bypass work brought it back into view.