On the 1933 edition of the Ordnance Survey six-inch map of County Galway, a hachured feature, meaning a marking made with short radiating lines used to indicate a depression or earthwork, was recorded at Cappaghnanool. By the time anyone went to look for it in person, in 1983, it was gone. A house stood in its place, and the ground gave no hint that anything had ever been scooped or hollowed there.

The cartographic evidence suggested the feature had been a pit or hollow of some kind, and the site was tentatively identified as a quarry. Small, localised quarries of this sort were common across rural Ireland from the eighteenth century onward, often dug to extract limestone or gravel for road-making or agricultural improvement, then abandoned and forgotten within a generation or two. Because the Cappaghnanool feature dated to after AD 1700, it fell outside the scope of formal archaeological classification, placing it in that slightly awkward category of things that are historically real but administratively invisible. Fifty years passed between the map being printed and the inspection being carried out, which was evidently long enough for a depression in the earth to be built over and erased entirely.