It does not announce itself with earthworks or a rise in the soil. It exists, as far as most evidence goes, only in the air, visible purely as a cropmark, the kind of faint signature that centuries of agriculture have pressed into the land and that only a camera at altitude can read.

Cropmarks form when buried features, walls, ditches, or compacted soil, affect how crops grow above them. Where a buried ditch retains more moisture, plants grow taller and greener; where a wall or floor lies close to the surface, they grow sparse and pale. From the ground, none of this is perceptible. From the air, the outlines of entire structures can emerge, especially during dry spells when the differences in soil moisture become most pronounced. It was precisely this effect that revealed the Lurgoe enclosure on an aerial photograph taken in 1995, and with it the suggestion of an associated field system nearby. The ridge on which all of this sits offers good views in every direction, the kind of elevated position that was often deliberately chosen for settlement or agricultural organisation in earlier centuries, though without further investigation the enclosure's date and function remain open questions.