That, in a sense, is precisely what makes it interesting. On a gentle south-facing slope in County Wexford, the outline of a rectangular enclosure roughly forty metres across in each direction survives not as earthwork or masonry, but as a cropmark, a ghostly imprint that only becomes legible from the air.

Cropmarks appear when buried features, ditches, walls, or pits, affect how plants grow above them. A filled-in fosse, the term for a defensive or boundary ditch dug around an enclosure, retains moisture differently from the surrounding soil, causing the crops or grass overhead to grow at a slightly different rate or colour. Seen from above at the right season, these variations resolve into shapes that would otherwise be invisible. At Summertown, that shape is a near-square enclosure defined by a single fosse, its form captured in aerial photographs. The roughly equal north-south and east-west dimensions suggest a deliberate, organised layout, though without excavation it is not possible to say with certainty what the enclosure contained or when it was built. Rectangular enclosures of this kind are known from various periods in Irish archaeology, and without further investigation the Summertown example remains suggestive rather than fully explained.