On the 1947 to 1948 revision of the Ordnance Survey six-inch map, it was marked with hachures, the small radiating lines cartographers use to indicate a slope or hollow, which gave it an air of significance. When someone finally went to look in 1985, the feature turned out to be a disused gravel pit, almost certainly dug after 1700.

The ridge itself is a product of glaciation, one of the long narrow landforms left behind as ice sheets retreated across the west of Ireland after the last Ice Age. Gravel pits like this one were worked whenever local demand arose, typically for road-making or drainage, and then abandoned when the material ran out or the need passed. They leave behind a characteristic bowl shape in the ground, which can persist in pasture for generations and occasionally catch the eye of a mapmaker or a field surveyor. This particular example, quiet and unremarkable from a distance, spent decades as an unexplained symbol on a map before being identified for what it was.