At Ardnabourkey in County Cork, a field that has been under the plough for generations holds the ghost of a lios, the Irish term for a roughly circular or rectangular earthen enclosure, typically a raised ringfort surrounded by a bank and ditch, that served as a farmstead or place of habitation during the early medieval period. There is nothing to see here. No bank, no ditch, no shadow in the grass. The site survives only as a name on old maps and a line in a county inventory.

The 1842 Ordnance Survey six-inch map recorded it clearly enough: a rectangular enclosure measuring approximately 35 metres east to west and 25 metres north to south, sitting on level ground at the base of a north-facing slope. By 1940, when the antiquarian Power noted it in print, it had already gone, described at that point as a square lios of moderate size that had, in his words, unfortunately been levelled. The tillage that replaced it has continued since, and with it any remaining trace of the earthworks has been turned under. What the 1842 surveyors captured on paper was probably already a diminished thing, a low ring of earth in a field, the kind of feature that becomes invisible the moment farming pressure increases.