There is nothing to see at ground level, and that absence is itself the point. The sites were identified not by excavation or fieldwork but through aerial photography, where differences in crop growth, known as cropmarks, revealed circular patterns invisible to anyone standing in the field below. Cropmarks form when buried features such as ditches or banks affect how plants grow above them, producing subtle variations in colour and height that only become legible from altitude.

The two circular features were recorded on separate aerial photographs, one black and white taken from 5,200 feet and one colour photograph taken from slightly lower at 5,000 feet. Each appeared to measure approximately 20 metres in diameter. They have been interpreted as ploughed-out barrows, that is, prehistoric burial mounds whose earthworks have been so thoroughly reduced by centuries of agricultural activity that no surface trace remains. By the time a ground survey was carried out in the 1990s, the field had undergone intensive reclamation and deep ploughing for barley cultivation, and neither site left any physical impression whatsoever. What the camera recorded from over a mile up had already been erased at the level of the soil. The two ring-ditches at Knockavinnane now exist, in any meaningful sense, only as photographs taken from an aircraft and as coordinates on a map.