At Carrowntober in County Galway, one such feature on the 1933 edition of the six-inch OS map turned out, when someone finally went to look in 1983, to be a gravel pit. Useful once, no doubt, for road-making or building work on nearby land, and now simply a hollow in a Connacht field with a faint cartographic afterlife.

The gap of fifty years between the map and the inspection is its own small story. The 1933 OS six-inch series was a revision of surveys that stretched back to the nineteenth century, and features were sometimes carried forward from earlier editions, their original purpose long since forgotten by anyone living nearby. When the pit was assessed in 1983, its post-1700 date placed it outside the scope of formal archaeological recording, which generally concerns itself with material from earlier periods. That boundary is a practical one rather than a judgement of significance, and it does mean that working landscapes of the eighteenth and nineteenth centuries, the quarries, pits, field drains, and lime kilns that shaped rural Ireland just as surely as any ringfort, tend to slip through the documentary net.