The feature, roughly 23 metres in diameter, was recorded as a quarry or sand pit on the first edition Ordnance Survey six-inch map of 1839, one of the great nineteenth-century efforts to document Ireland's landscape in systematic detail. By the time a revised map was produced in 1947, it had vanished from the cartographic record entirely, most likely filled in over the intervening century.

What makes the site quietly interesting is what happened when an aerial photograph was taken on 13 July 1989. Cropmarks, the subtle variations in vegetation colour and growth that reveal buried or disturbed ground beneath a field, brought the quarry back into view. The circular edge of the old pit showed up clearly enough that it could be mistaken for a fosse, the term used for the defensive ditch surrounding a ringfort or similar earthwork. It is a neat case of mistaken identity made possible only by time and seasonal dryness, the conditions under which cropmarks tend to appear most legibly. The ground had been altered, the alteration buried, and then the buried shape quietly reasserted itself through the roots of whatever was growing above it.