In May 1977, an aerial photograph captured what the ground itself conceals: a cropmark, that faint but legible language by which buried archaeology speaks to those looking down from above. The mark showed a rectangular area ringed by a wide band of lighter-coloured growth, the kind of variation that occurs when buried ditches or disturbed soil affect how crops or grass draw moisture, causing them to grow differently from their surroundings.

Cropmarks of this kind are typically the surface signatures of enclosures, a broad category of archaeological feature that includes everything from prehistoric farmsteads to early medieval ringforts and field boundaries. The rectangular form here is worth noting: circular and oval enclosures are far more common across the Irish landscape, making a rectangular outline comparatively unusual. Whether the underlying feature is a field system, a settlement boundary, or something else entirely, no excavation appears to have established its date or precise function. The photographic record, taken by the Geological Survey of Ireland Air Photography unit in 1977, remains the primary evidence.