On the ground near Ballyhooly in north Cork, there is nothing obvious to see; the enclosure has long since been absorbed into farmland. But in an aerial photograph taken in July 1989, the buried past reasserted itself in the form of cropmarks, the subtle discolouration of growing crops that follows the lines of underground features, revealing what soil alone conceals. What appeared was the outline of two concentric circular ditches, or fosses, forming a roughly circular enclosure about forty metres across, with an entrance gap facing south-east.

The double-fosse arrangement and circular form place this firmly within the tradition of the ringfort, the most common type of early medieval settlement monument in Ireland. Ringforts, typically dating from roughly the sixth to the twelfth centuries, served as enclosed farmsteads, with the bank and ditch providing a degree of security for people and livestock. The concentric ditches here suggest a structure of some elaboration, since a second outer fosse was an additional investment of labour, sometimes associated with higher-status sites. Along the southern side of the enclosure, the cropmarks hint at two possible annexes or subsidiary field enclosures, areas that may have functioned as stock pens or garden plots. More intriguing still is the eastern edge, where the outer fosse appears to overlap slightly with the ditch of a neighbouring enclosure, suggesting these features developed in close proximity to one another, perhaps contemporaneously. Two further possible ringforts have been identified in the same field, making this a small but telling cluster of early settlement activity concentrated in one corner of the Blackwater valley.