It is neither. The mound is a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, typically Bronze Age in origin. The method involved heating stones in a fire, dropping them into a water-filled trough to bring it to a boil, and then using that hot water to cook meat. Over repeated use, the cracked and spent stones were raked out and piled up, forming exactly the kind of scorched, curved mound visible here.

The mound at Carrigagulla measures nine and a half metres in both length and width, rising to about sixty centimetres at its highest point. Its opening, four metres wide, faces south-west, and a smaller secondary mound of burnt material sits immediately outside that opening, measuring three metres by two metres and standing about thirty centimetres high. The proximity to a stream is entirely typical. Fulachtaí fia are almost always found near a reliable water source, which was essential to their function. The scorched and fragmented stone that makes up the mound gives these sites their characteristic dark, heat-reddened appearance when disturbed, though at Carrigagulla the vegetation has done much to soften the outline over time.