The catch is that nobody can see it anymore. The archaeology, if it survives at all, lies entirely below the surface, swallowed up by the practical business of farming.

What we know comes largely from a map. A revision of the Ordnance Survey six-inch sheet, itself based on the original 1834 survey and updated in 1858, shows a circular earthwork sitting on a low spur of land running roughly south to north. Just to the south of it, a house is marked in the italic lettering that nineteenth-century cartographers used to distinguish antiquities and named features from ordinary buildings. That house is labelled 'Fort Johnson', a name that suggests the earthwork was still recognised, at least in local usage, as something old and deliberate. Whether the Johnson in question was a family name attached to the property or something older is not recorded. By the time anyone looked closely at ground level, nothing remained visible to confirm what the map had shown.