At Lattoon in County Galway, there is an archaeological site that exists today only as a cartographic memory, a circular enclosure roughly 25 metres in diameter that was recorded on the third edition of the Ordnance Survey six-inch map in 1932 and has left no visible trace on the ground since. The land is under tillage, and whatever earthwork once defined this circle, whether a raised bank, a shallow ditch, or some combination of both, has been levelled entirely by generations of ploughing.

Circular enclosures of this kind are common features of the Irish archaeological landscape, and they vary enormously in date and function. Some are the remains of ringforts, the enclosed farmsteads that were the dominant settlement type in early medieval Ireland, typically bounded by an earthen bank and ditch. Others may be later in origin, or earlier. Without excavation it is rarely possible to say which category a particular example belongs to. What the 1932 map records is the outline of something that was, at that point, still legible enough to a surveyor to be worth marking down. At some point between that survey and the present, the enclosure crossed the threshold from degraded monument to no monument at all.

There is a particular kind of historical melancholy in sites like this one. The map entry in the 1999 Archaeological Inventory of County Galway, compiled by Olive Alcock, Kathy de hÓra, and Paul Gosling, is essentially an obituary, noting what was there and confirming that it is gone. The enclosure at Lattoon is now best understood not as a place to visit but as a reminder that the archaeological record is not a fixed thing; it erodes, gets ploughed under, and occasionally survives only in the marginal notations of an old Ordnance Survey sheet.