The site is a fulacht fia, or so the maps suggest, and the overgrowth has had the last word on the matter.

A fulacht fia is a type of ancient cooking or processing site found across Ireland in enormous numbers, typically identified by a horseshoe-shaped or subcircular mound of burnt and shattered stone. The general theory is that stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, the cracked and discarded stones gradually accumulating into the low mound that survives. The Garraun example appeared on an Ordnance Survey six-inch map from 1937, marked as a small subcircular mound to the east of a stream, in what is now described as scrubland. When surveyors went to verify it on the ground, the vegetation had closed in entirely and the site could not be located. It remains, technically, a recorded monument, fixed in the record at a particular point on a 1937 map, while the landscape quietly refuses to cooperate.