This one in Ballymartin, County Limerick, offers nothing of the sort. It exists almost entirely as an absence, a ghost written into the grass rather than into stone, and it has managed to evade the historical record entirely until the age of aerial photography brought it reluctantly to light.

The enclosure does not appear on the Ordnance Survey's six-inch map of 1840, nor on the more detailed twenty-five-inch survey carried out in 1897, which suggests it had already lost any surface expression long before those surveys were made. It came to attention in 1986, when aerial photographs taken during work on the Curraleigh to Limerick gas pipeline were examined and the site was identified from the photographic record compiled at a scale of 1:10,000. A cropmark, the term for the differential growth of crops or grass above buried archaeological features, which can reveal the outline of ditches, walls, or pits invisible at ground level, was what gave it away. When archaeologists from the Archaeological Survey of Ireland visited in 2000, they found no surface remains whatsoever. The site sat in pasture on a gentle north-northwest-facing slope, roughly 120 metres south of the townland boundary with Kilderry, and it looked, to the naked eye, like any other field. A further faint cropmark was subsequently detected on a Google Earth orthoimage captured on 28 June 2018, confirming that something does lie beneath, even if its date, function, and precise form remain unrecorded.

There is nothing to see here in any conventional sense, and that is precisely what makes the site worth knowing about. It sits in working farmland, and visitors should be mindful that the land is private. The cropmark phenomenon that revealed it is most legible from the air during dry summers, when buried features affect the moisture available to surface vegetation and produce subtle tonal differences across a field. On the ground in ordinary conditions, you would walk straight over it. The record, compiled by Martin Fitzpatrick and uploaded to the national Sites and Monuments database in August 2020, stands as a reminder that the Irish landscape holds a great deal that has not yet been named, dated, or understood, detected only when light and drought and the angle of a camera lens happen to align.