It is the kind of thing you could walk past without a second glance, yet it represents a form of prehistoric activity found in extraordinary numbers across the Irish landscape. This is a fulacht fia, a type of ancient cooking or processing site consisting of a horseshoe-shaped mound of heat-shattered stones left over from repeated cycles of heating and water boiling. The characteristic shape comes from the gradual accumulation of those spent stones, discarded after they cracked and lost their usefulness, around three sides of a central trough or pit. The mound here measures roughly 8.5 metres north to south and 8 metres east to west, rising to about 0.9 metres at its highest point, with a 2-metre opening facing east, directly towards the stream beside it.

The proximity to water is no coincidence. Fulachtaí fia, the plural form, are almost always found close to a water source, since the process they served involved heating stones in a fire and then dropping them into a water-filled trough to bring it rapidly to the boil. Thousands of these sites have been recorded across Ireland, most dating to the Bronze Age, roughly 1500 to 500 BC, though some extend earlier or later. What exactly they were used for remains a lively question among archaeologists: cooking large quantities of meat is the traditional explanation, but brewing, textile processing, and bathing have all been proposed. The mound at Derrycreeveen sits in pasture on the western side of a stream, its charcoal-enriched soil a trace of the fires that once fed the process. A possible second burnt mound lies approximately 65 metres to the south-west, suggesting this corner of Bear Island saw repeated or prolonged use of the same kind.