This one is defined by what was not. At Dunsink in County Dublin, a low-lying stretch of riverside land holds the ghost of something that may once have been a ring-ditch, a roughly circular earthwork cut into the ground, typically associated with prehistoric burial or ritual activity. It survives not as a visible feature in the landscape but as a cropmark on a single aerial photograph, reference FSI 0.148/9, showing a circular mark roughly fifteen metres in diameter. Whether that faint impression ever constituted a genuine archaeological monument is a question that can no longer be answered.

The area was investigated in 1991, but the excavation produced no archaeological deposits whatsoever. The reason, recorded by Keeley in 1991, is straightforward and a little dispiriting: before the investigation could take place, the topsoil had already been stripped from the site, taking with it whatever physical evidence may once have lain there. What the aerial photograph captured, in other words, was likely all that remained even before archaeologists arrived. The site was compiled in the national record by Geraldine Stout and uploaded in August 2011, preserved in the archive as a cautionary entry, a possible monument whose possibility has been permanently foreclosed.

There is nothing to see at Dunsink in the conventional sense. The site sits in a low-lying riverside setting north-west of Dublin city, and the land shows no surface trace of any feature. For anyone with an interest in how archaeology actually works, though, this entry in the record is instructive in its own quiet way. It documents not just a monument but the circumstances of its loss, and the role that routine groundworks, in this case topsoil removal, can play in erasing the material past before anyone has had a chance to read it. The aerial photograph remains the sole evidence, and even that only suggests what might have been there.