The disturbance brought up burnt material in clumps along the drain for about twelve metres, the telltale signature of a fulacht fia.

A fulacht fia is a type of prehistoric cooking or heating site found widely across Ireland, typically consisting of a trough, a hearth, and a mound of fire-cracked stone, the debris that accumulates when rocks heated in a fire are used to boil water. The mounds, often horseshoe-shaped and dark with charred material, are among the most common ancient monument types in the country, though they tend to survive quietly in marginal ground, in bogs, or near water sources. The Glantane example sits on the southern side of a drainage channel, which fits the pattern well: proximity to water was a practical necessity for whatever activity the site supported. Its exposure was essentially accidental, a consequence of construction rather than targeted excavation, and what came to light was not a neat, preserved mound but dispersed burnt material spread through the soil along the drain.