In the grassland of Feaghmore Eighter in County Galway, a shallow depression in the ground is all that remains of a disused gravel pit, the kind of feature that could pass entirely unnoticed underfoot.

The pit came to light through cartographic detective work of a modest but instructive kind. On the 1944 to 1945 revision of the Ordnance Survey six-inch map, a hachured feature, meaning a small mark used to indicate a change in ground level or a hollow, had been recorded at this location. When the site was inspected in 1984, the feature turned out to be nothing more ancient than a worked-out gravel pit, its edges softened over time into a slight depression in the turf. Because it dates to after 1700, it falls outside the scope of formal archaeological classification, which in Ireland generally concerns itself with earlier remains. The gravel pit is therefore a kind of negative space in the record, present enough to be mapped and visited, absent enough to be formally excluded.