That is the situation at Moheraroon in County Clare, where what looked from the air like a potentially ancient feature resolved itself, during a 1997 survey visit, into a subcircular enclosure roughly forty metres across, its boundary built in relatively recent times rather than early medieval or prehistoric ones.

The setting is genuinely interesting, even if the structure itself is not ancient. The enclosure sits at the southern edge of a low plateau in an area of limestone pavement, the kind of exposed karst terrain that Clare is well known for, where the bare rock surface is broken by grikes and clints and covered, where soil has gathered, by a thin mat of grass. Features like this can be difficult to date or characterise from aerial photography alone, and the site had been carried forward from the 1992 Sites and Monuments Record into the 1996 Record of Monuments and Places on the basis of its visible outline. The 1997 inspection clarified matters, though the record was retained, a reminder that the archaeology of a landscape is sometimes the story of what turns out not to be there as much as what is.