On Ordnance Survey maps from 1836 and 1906, a cluster of stones appears southwest of a feature called the 'Giants Bed'. The 1836 edition simply labels them 'Stones', whilst the 1906 map intriguingly upgrades them to 'Standing stones'. When researchers went looking for these stones in the late 20th century, they found nothing; the monuments had seemingly vanished without a trace.

The plot thickened in 2011 when excavations revealed that the nearby Giants Bed was actually a Neolithic cairn, dating back thousands of years. During the same dig, archaeologists made another discovery: a wedge tomb sat immediately southwest of the cairn, exactly where the mysterious standing stones had been marked on those old maps. This raised an intriguing possibility; perhaps the Victorian cartographers had been recording this ancient tomb all along, though they didn't quite know what they were looking at.

So what became of these standing stones? Several theories compete for the truth. They might have been part of the cairn itself, removed during the 19th century when locals helped themselves to the monument's stones for building materials, a common practice at the time. Alternatively, the 'standing stones' marked on those maps might have been the wedge tomb's upright stones, misidentified by early surveyors. Or perhaps there really was a separate stone monument here once, now lost to time and human interference. Without a time machine, we may never know for certain what those Victorian mapmakers saw at Croaghonagh, adding another layer to Ireland's rich tapestry of archaeological mysteries.