It is, in fact, the remains of a fulacht fia, one of the most common yet persistently mysterious monument types in the Irish landscape. These are the scorched debris mounds left behind by a Bronze Age practice of heating stones in fire and dropping them into water-filled troughs to bring the water to the boil, though what exactly the process was used for, whether cooking, bathing, textile preparation, or something else entirely, remains a matter of genuine scholarly debate.

The site at Kilberrihert follows the typical pattern: a spread of fire-cracked stone, often mixed with charcoal and dark soil, accumulating over repeated use into a low horseshoe or kidney-shaped mound. Fulachtaí fia tend to cluster near water sources, which makes the proximity to the drain here entirely consistent with the type. Ireland has thousands of these monuments, the great majority dating to the Bronze Age, and Cork is particularly well-supplied with them. Most go unnoticed precisely because they look like nothing more than a slight rise in a field.