It takes an aeroplane and the right conditions to reveal it: a series of rectilinear cropmarks, some running perpendicular to each other, spread across approximately six hectares of farmland. Cropmarks appear when buried features such as old walls, ditches, or banks affect how the soil retains moisture, causing the crops above them to grow at subtly different rates or colours. From the air, that variation reads as geometry, and at Subulter the geometry suggests a organised field system of some antiquity.

The site came to light through aerial photography carried out in July 1989 as part of the Cork Archaeological Survey Aerial Photography programme. The photographs captured the cropmarks during the summer months, which is typically when differential crop growth is most pronounced and such features are easiest to read. The rectilinear layout, with boundaries meeting at or near right angles, points to deliberate land division rather than natural formation, though without excavation it is difficult to assign the system a precise period or function. Field systems of this kind in Ireland range from the prehistoric to the early medieval, and the north Cork landscape contains numerous traces of past agricultural organisation that surface only under particular conditions of light and season.