That, in a way, is exactly the point. Somewhere beneath the pasture grass, or more accurately spread across the surrounding land during agricultural reclamation works, lie the last traces of what was probably a fulacht fia, one of the curious burnt mounds that appear throughout the Irish countryside and represent one of the most common, and least fully understood, monument types in the country.

A fulacht fia is, in its simplest form, a mound of fire-cracked stone and scorched earth, the accumulated debris of a cooking method in which water was heated by dropping stones that had been superheated in a fire directly into a trough or pit. The process was repeated over time, leaving crescents or horseshoe-shaped mounds of shattered stone that can survive for thousands of years. At Ballygriffin, local knowledge recorded a mound of burnt stone and black earth on rough ground close to a stream, a typical setting since a reliable water source was essential to the whole operation. During land reclamation, that mound was levelled and its material spread, and the field has since returned to ordinary pasture with no visible remains surviving at the surface.