On the six-inch Ordnance Survey map published in 1931, a hachured marking in the rolling pastureland of St Brendan's in County Galway suggested, to the trained eye, some kind of earthwork or topographical irregularity worth noting. Hachuring, the system of short radiating lines used by cartographers to indicate slopes or raised ground, can imply ancient enclosures, earthen banks, or features of archaeological significance. When someone finally went to look in 1984, the reality was more modest: a disused gravel pit, its presence registered now only as a hollow in the grass.

Gravel pits of this kind were a practical necessity across rural Ireland throughout the nineteenth and into the twentieth century, supplying loose material for road surfacing, farmyard drainage, and general land improvement. They were dug where the geology permitted, used until exhausted, and then quietly abandoned, leaving depressions that slowly softened into the surrounding land. The St Brendan's example is thought to date from somewhere within that broad nineteenth or twentieth century span. It was ordinary work, carried out without record, and the hollow it left behind is the only evidence that it happened at all. The fact that a cartographer thought it worth marking, and that a surveyor later went to check, gives it a small, accidental significance it was never meant to have.