An aerial photograph taken on 16 July 1989 captured what is known as a cropmark, the faint but legible trace of a ring-ditch showing through the grass and grain above it. Cropmarks form when buried features, ditches, pits, or walls, affect how deeply plants can root, causing subtle differences in growth and colour that become visible from altitude, particularly during dry summers when the contrast sharpens. The ring-ditch at Moorstown would be invisible to anyone walking the field.

Ring-ditches are generally the eroded remains of prehistoric burial monuments, most often round barrows whose central mounds have been levelled over millennia of agriculture. What survives underground is the circular ditch that once surrounded the mound, and it is this hollow, filled with darker, moister soil, that the cropmark reveals. The Moorstown example sits close to a separate circular enclosure recorded about fifty metres to its north, suggesting this corner of Tipperary was a place of some significance in the prehistoric landscape, with monuments clustering in the way that was common around burial grounds and ceremonial sites.