In the St Brendan's area of County Galway, one such marking appeared on the 1931 edition of the six-inch OS map, intriguing enough on paper but rather more prosaic in reality.

When the feature was inspected in 1984, it resolved itself into a disused sand pit, visible now only as a shallow hollow set within pastureland. Sand pits of this kind were common working features of rural Ireland during the nineteenth and early twentieth centuries, dug to supply local construction and agricultural needs before commercial extraction made small-scale pits redundant. The St Brendan's example is thought to date from that same broad period, somewhere in the span between the mid-1800s and the early decades of the twentieth century, though no more precise date has been established. What remains is little more than a depression in a field, the kind of subtle landform that farmers work around without much thought and that only a close reading of an old map would prompt anyone to investigate further.