On high ground along the townland boundary between Cullentragh Little and Ballybraid in County Wicklow, there is a stone that looks, at a glance, like a relic of prehistoric ritual. It is almost certainly nothing of the sort. The stone appears to have been planted in the landscape by surveyors, not by ancient hands.

The stone first shows up on the 1908 to 1909 edition of the Ordnance Survey six-inch map, which is a relatively recent appearance for something that might otherwise pass for a megalithic monument. Its position is telling: it sits on elevated ground precisely where the two townlands meet, and the most plausible explanation is that it was erected by the Ordnance Survey itself to serve as a boundary marker. The OS carried out extensive mapping work across Ireland from the 1820s onwards, and their surveyors were not above placing physical markers in the field to fix points on the ground. A stone set on a prominent ridge to delineate where one townland ends and another begins would have been a practical, unremarkable act at the time, even if it now carries the ambiguous silhouette of something far older.