On a July day in 1989, an aerial photograph captured it clearly: a cropmark tracing the outline of a curvilinear enclosure roughly 50 metres in diameter, defined by two widely spaced, concentric fosses. A fosse is simply a ditch, and in enclosures of this kind two of them, set apart from each other, would originally have formed a substantial boundary around whatever lay at the centre. The enclosure is incomplete as the cropmark shows, meaning either part of it was never finished, or the ditches have survived unevenly in the soil.

Cropmarks appear when buried features, ditches, pits, or walls alter how plants grow above them. Ditches filled with looser soil tend to hold more moisture, encouraging crops to grow taller and stay greener longer, while stone foundations beneath the surface can have the opposite effect. From ground level these differences are imperceptible, but from altitude, especially in dry summers when the contrast sharpens, buried archaeology can resolve itself into precise geometry. The Archersgrove enclosure sits approximately 120 metres from Archersgrove House, meaning a monument of considerable scale lies just within sight of a later, named residence, the two occupying the same landscape across a considerable gap in time.