Cropmarks form when buried features, ditches, walls, or banks alter how crops above them grow; slight differences in soil moisture and depth produce variations in colour and height that become readable in aerial photographs, particularly during dry summers when the contrast is most pronounced. What appeared in photographs taken on 14 July 1970 and again on 18 July 1970 was a rectilinear feature, that is, a roughly rectangular arrangement of lines suggesting deliberate, organised land division rather than anything accidental or natural.

The feature is thought to be part of a field system connected to a nearby enclosure that adjoins the site to the north. Enclosures of this kind in the Irish landscape served various purposes across different periods, from ringforts used as defended farmsteads in the early medieval era to earlier boundary structures, and the field system around them often reflects how the surrounding land was managed and worked. A second, separate field system has also been identified in aerial photographs, extending northeastward from the same enclosure before turning south; crucially, it sits on a noticeably different axis from the system to the south, suggesting the two arrangements may belong to different phases of land use, or reflect distinct approaches to organising the same ground. The two systems together hint at a more layered history of agricultural activity than the bare field surface would suggest. Since around 2011, a farm roadway running broadly east-northeast to west-southwest has cut across the rectilinear feature, and an earlier modern field boundary visible in the 1970 photographs has since been removed, meaning the contemporary landscape has continued to shift even as the buried one endures beneath it.