That dotted line indicates a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, typically identified by a horseshoe-shaped mound of burnt and cracked stone, the discarded residue of repeated heating. Fulachtaí fia are usually found close to water or boggy ground, which made them practical: water was collected in a trough, stones were heated in a fire nearby, and the hot stones were dropped into the trough to bring the water to a boil. The marshy setting here fits that pattern precisely.

What makes this particular site quietly interesting is how little is certain about it. When it was recorded, burnt material had not been positively identified within the mound itself, leaving its interpretation provisional. It sits roughly forty metres south of a second fulacht fia, suggesting this small area of ground was returned to repeatedly, or that activity here was more concentrated than a single site would imply. The 1938 Ordnance Survey mapping provides the earliest reliable documentary reference, though the archaeology almost certainly dates to the Bronze Age, the period, broadly spanning from around 2000 to 500 BC, when fulachtaí fia were most widely used across the Irish countryside.