In a stretch of reclaimed pasture in County Limerick, somewhere in the barony of Coshma, a possible ancient enclosure lies beneath ordinary grazing land, leaving no mark visible to the naked eye or to satellite cameras. It has never appeared on the Ordnance Survey's historic maps, and as of September 2020, Google Earth showed nothing but unremarkable grass. The site is known to archaeology not because anyone found it on the ground, but because a camera mounted in an aircraft caught a fleeting impression of it from above.

The story of how it entered the record is almost as interesting as the site itself. In 1986, an aerial photographic survey centred on the town of Bruff, a few kilometres away in south County Limerick, picked up what was logged as a possible enclosure in a field near the townland boundary with Milltown. The reference, Bruff 45, AP 5/2069, sits in survey records alongside the photograph that preserves this ghost of a feature. Aerial archaeology works by detecting cropmarks or soilmarks, subtle differences in how vegetation grows or soil colours over buried features, differences invisible at ground level but legible from height. An enclosure in this context would likely mean a roughly circular or oval earthwork, the kind of boundary that in Ireland most often dates to the early medieval period, though without excavation the date and function of this one remain entirely open. Milltown House, a more recent landmark, stands some 190 metres to the north-east, and a watercourse marking the townland boundary runs roughly 100 metres to the east.

A visitor in search of this site would find the exercise more archival than physical. There is nothing to see at ground level, and the record makes clear that even remote sensing has yielded only ambiguous traces. The relevant aerial photograph, taken during the 1986 Bruff survey, is the closest thing to a view of the feature that currently exists. The site was compiled and uploaded to record by Martin Fitzpatrick in June 2021, part of the slow, careful work of cataloguing possible sites that might otherwise never be formally noted. For anyone interested in how landscape archaeology actually functions, this is a useful illustration: much of what may be buried in the Irish countryside exists, for now, only as a number in a survey log and a faint mark on old film.