This is a fulacht fia, a class of prehistoric cooking site found in enormous numbers across Ireland, typically identified by its distinctive horseshoe-shaped mound of burnt and fragmented stone. The mound at Barr An Tseanchnoic is modest, four metres long and three-quarters of a metre high, but what it represents stretches back thousands of years.

The mechanics of a fulacht fia are straightforward enough. A trough, usually timber-lined or cut into the ground near a water source, would be filled with water, and stones heated in a nearby fire would then be dropped in to bring the water to a boil. The shattered, fire-cracked stones, spent and useless after one or two uses, were piled to the side, and over generations of repeated use these discards accumulated into the low, spread mounds that survive today. The proximity to a stream at this site fits the pattern precisely: a reliable water source was not incidental but essential. Most examples date to the Bronze Age, roughly 1500 to 500 BC, though some have earlier or later origins. The function of these sites has been debated at length; cooking is the most widely accepted explanation, but proposals have ranged from bathing and textile processing to more ceremonial uses.

The burnt material exposed in the field fence here suggests the mound has been partially disturbed, possibly during the construction or maintenance of the boundary, which is how many such sites first come to light across Irish farmland.