Beneath the turf, however, the mound is composed almost entirely of heat-shattered stones and charcoal-enriched soil, the characteristic signature of a burnt mound, a type of prehistoric site found across Ireland and Britain in considerable numbers.

Burnt mounds, known in Irish archaeology as fulachtaí fia, are among the most common prehistoric monument types in Ireland, though their precise function has been debated for decades. The prevailing interpretation is that they were cooking sites: stones would be heated in a fire, then dropped into a water-filled trough to bring the water to the boil, and the cracked, discarded stones would accumulate over time into the distinctive mound shape. Brewing, textile processing, and bathing have also been proposed as possible uses. The site at Teeveeny fits this profile closely, its fractured stones and dark, carbon-rich soil consistent with repeated cycles of heating and discard over what may have been a considerable period. A modern agricultural drain now cuts across the northern edge of the mound, a small truncation that hints at how many such sites across the country have been partially lost to land improvement works over the centuries.