It exists only as a pattern in the soil, invisible from the surface, revealed solely because a magnetometer was dragged across the ground and measured tiny variations in the earth's magnetic field beneath.

The enclosure, roughly 32 metres in diameter, was identified during a magnetic gradiometer survey, a technique that detects buried features such as ditches, pits, and banks by recording differences in the magnetic properties of disturbed or burnt soil against the undisturbed ground around it. What emerged from the data were faint, interrupted traces of either a fosse, which is a defensive or boundary ditch typically associated with early medieval ringforts or enclosures, or a series of individual pits following the same rough circuit. The site sits on land that once formed part of the demesne of Coolcliffe House, the private estate grounds that would have surrounded the country house of the same name. That agricultural and estate history may partly explain why so little survives above ground; centuries of ploughing and land management can reduce even substantial earthworks to near-nothing, leaving only the chemical and magnetic memory of what was once there.