This is a burnt mound, known in Irish archaeology as a fulacht fiadh, one of the most common yet least celebrated prehistoric monument types in Ireland. The basic principle is straightforward: stones were heated in a fire, then dropped into a water-filled trough to bring it rapidly to the boil. The spent, cracked stones were discarded in a pile nearby, and over generations that pile accumulated into the low, rounded spreads archaeologists find today. At Ballykinealy, the spread measures roughly thirty metres across in both directions, suggesting the site saw repeated and sustained use.

Burnt mounds of this kind are generally associated with the Bronze Age, broadly spanning from around 2000 BC to 500 BC, though some examples fall outside that range. Their precise function has been debated for decades. Cooking is the most widely accepted explanation, though scholars have also proposed industrial processes, hide-working, and communal bathing. The charcoal-enriched soil recorded at Ballykinealy is typical of the type, reflecting the sustained burning that went on over what may have been a very long period of intermittent activity. The low-lying, level ground near the bay would have provided reliable access to water, which any fulacht fiadh required to function.