The feature appeared on the 1920 edition of the OS 6-inch series as a hachured marking, the cartographic shorthand surveyors used to indicate a hollow or slope in the terrain, suggesting something of enough physical distinctness to record. When someone went out to look at it in 1983, the mystery resolved itself simply: it was a disused gravel pit, defined by a shallow hollow, and nothing more ancient than that.

The gravel pit dates to after 1700, which places it firmly in the era of post-medieval land use, when local extraction of gravel and stone for road-making and estate improvement was commonplace across rural Ireland. Such pits were dug as needed, worked until the material was exhausted or no longer convenient to reach, and then abandoned, leaving behind only a gentle scar in the landscape. What is quietly interesting about Lackabaun is less the pit itself than the bureaucratic fact of its investigation: someone, at some point, looked at that hachured smudge on a sixty-year-old map and considered it worth a visit to determine what it actually was. The answer turned out to be unremarkable, but the impulse to check is its own kind of record, a reminder that landscape features accumulate significance simply by being noticed and written down.