The spot was mapped in 1842 as a hachured circular enclosure, the kind of shorthand surveyors used to indicate a roughly circular earthwork, perhaps a ring fort or some earlier enclosure, around twenty metres across. When investigators eventually went looking for it on the ground, they found nothing. The boggy, overgrown terrain had been cut through by numerous drainage ditches, and whatever the original cartographer thought they were recording had either vanished entirely or was never there to begin with.

What makes this particular absence interesting is the name the place acquired in the meantime. By the time the Ordnance Survey revised its six-inch maps in 1906, and again in 1937, the site was being labelled not as any kind of ancient monument but as Knockanare Fox Covert, suggesting that in the intervening decades the ground had been managed, at least loosely, as a woodland shelter for foxes in connection with hunting. The original circular feature that caught a surveyor's eye in 1842 had been quietly reclassified by the landscape itself, absorbed into agricultural and sporting use along the river. Whether the enclosure marking was an error of observation, a misread field boundary, or the last trace of something that drainage works subsequently destroyed is now impossible to say with confidence.