In the scrubland at Derrybeg in County Galway, a hachured marking on the 1947 revision of the Ordnance Survey six-inch map, the kind of shading cartographers use to indicate a raised or irregular landform, sat on record suggesting something of possible archaeological interest on a small hillock. When someone finally inspected the site in 1983, what they found was simpler and more recent: a pit, most likely the remnant of a quarry, dug sometime after 1700.

The gap between the map and the reality is a small illustration of how landscape features accumulate significance simply by being recorded. Hachuring on an OS map carries a faint suggestion of antiquity, of earthworks thrown up in some earlier era, and so a depression in scrubland can sit in a kind of interpretive limbo until a physical visit resolves the question. In this case, the post-1700 date placed it firmly outside the scope of formal archaeological classification, which in Ireland generally concerns itself with features predating that threshold. The site at Derrybeg is not ancient, but it is a reminder that the worked and quarried landscape of the more recent past leaves its own marks, modest ones that can look, from a distance or on paper, rather more mysterious than they turn out to be.