Roughly twelve metres long, eight metres wide, and barely sixty centimetres high, it is unassuming almost to the point of invisibility. Cattle have worn down its top and eastern edge over the years, blurring its outline further. Yet this modest hump in the ground is the remains of a fulacht fia, a type of prehistoric cooking site found in considerable numbers across Ireland, and one of the more quietly compelling categories of monument the island has to offer.

Fulachtaí fia, the plural form, are generally understood to have been used for boiling water, most likely for cooking meat, by dropping fire-heated stones into a trough. The burnt and shattered stones, discarded after use and piled up repeatedly over time, form the distinctive horseshoe-shaped or irregular mounds that survive to this day. They tend to cluster near water, which explains the stream alongside this one, and in low-lying or boggy ground where a trough could be dug and would naturally fill. The majority date to the Bronze Age, roughly 2000 to 500 BC, though some sites have produced evidence of use across a wider span. The one at Assolas fits the type precisely: the waterside location, the boggy setting, the mound of burnt material built up through repeated episodes of use and discard.