It only became apparent from the air, when a pilot or photographer noticed the faint discolouration of crops growing above its buried ditch, or fosse. A fosse is simply a defensive or boundary ditch dug around a settlement or enclosure, and when it silts up over centuries, the soil above it retains slightly more moisture than the surrounding ground. In the right conditions, crops above it grow a little differently, and from altitude that difference reads as a ghostly outline pressed into the field.

The enclosure measures approximately thirty metres in diameter, a modest size consistent with a small ringfort or farmstead enclosure of early medieval date, though no firm dating has been established for this particular site. What makes its outline slightly unusual is the geometry: the eastern and southern sides run in straight lines, meeting at a rounded south-eastern corner, while the western and northern sides curve more naturally. That mixture of straight and curved elements is not the norm for the typical circular ringfort, and it hints that the original builders may have adapted their design to suit the terrain, a field boundary, or some earlier feature of the landscape. The cropmark was recorded in an aerial photograph taken in July 1967 as part of the Cambridge University Collection of Aerial Photography.