They appear as low, kidney-shaped or horseshoe mounds of fire-cracked stone and dark, charred soil, and the one at Moyriesk in County Clare is a local example of a monument type found in almost every townland in the country. What they were actually used for has kept archaeologists arguing for decades.

Burnt mounds, known in Irish as fulachtaí fia, date mostly to the Bronze Age, roughly 1800 to 800 BC, though some are older or younger. The standard interpretation is that they functioned as cooking sites: stones were heated in a fire, then dropped into a water-filled trough to bring it to the boil, shattering in the process and accumulating over time into the distinctive mound. The repeated cycle of heating and cracking is what gives these sites their characteristic appearance, the blackened, shattered stone mixed with organic material building up around the trough. More recent research has proposed additional or alternative uses, including textile processing, hide preparation, bathing, or even brewing, and the debate remains open. Clare has a particularly dense concentration of them, reflecting both the county's Bronze Age population and its boggy ground conditions, which help preserve organic material and hold the evidence in place.

Moyriesk itself is a small townland in east Clare, not far from Quin, in an area that was clearly well settled in prehistory. Without excavation, a burnt mound reveals relatively little at the surface beyond its characteristic shape and composition, but that low, dark rise in a field or at the edge of a wetland carries a considerable amount of time within it.