At Drummin in County Galway, a hachured marking on the 1920 edition of the Ordnance Survey six-inch map, the kind of fine hatching cartographers used to indicate slopes, depressions, or earthworks of uncertain character, turned out on physical inspection in 1982 to be nothing more, and nothing less, than a quarry. The feature had sat on the map for decades, unverified, its true nature left open to interpretation.

When a surveyor finally visited the site, the quarry was confirmed as post-1700 in date, which placed it outside the scope of formal archaeological classification. That boundary, AD 1700, is a practical threshold used to distinguish prehistoric and early historic remains from features belonging to the modern industrial or agricultural era. Quarrying of this kind was commonplace across rural Ireland from the eighteenth century onwards, typically serving local needs for building stone, road materials, or lime production. The Drummin quarry would have been unremarkable in its time, a working hollow cut into the landscape for practical purposes, then eventually abandoned and left to be read only as a cartographic curiosity by later generations.