On the 1932 edition of the Ordnance Survey six-inch map of County Galway, a hachured feature sits in the undulating pastureland around Castle Ffrench, its cross-hatched symbol suggesting an earthwork of some consequence, perhaps a rath or enclosure. When someone finally went to look in 1984, the feature turned out to be a shallow, irregular depression: a disused quarry pit, almost certainly dug sometime after 1700, and of no particular antiquity.

The story of the site is really the story of a cartographic ghost. Hachuring on older Ordnance Survey maps was used to indicate slopes and raised earthworks, and on a map read without ground-truthing, such a mark can carry an air of significance. The gap between the 1932 survey and the 1984 inspection is itself a reminder of how long a small ambiguity can persist on paper, unremarked in ordinary pasture, before anyone goes to check. Because the quarry post-dates AD 1700, it falls outside the scope of prehistoric and early historic archaeology, which is why it was examined and then set aside rather than excavated or protected.