Yet from the air, under the right conditions, the ground near Annamult in County Kilkenny gives itself away. When crops grow unevenly over buried features, they betray the outlines of what lies below, and at this site a roughly circular form roughly fifty metres across emerges as a cropmark, the faint signature of a fosse, or defensive ditch, that once defined an enclosure of some significance.

The evidence comes from a single aerial photograph taken on 16 July 1971 as part of the Cambridge University Collection of Aerial Photography. Cropmarks of this kind are most legible during dry summers, when moisture retained in the disturbed soil of a filled ditch keeps the plants above it slightly greener or taller than their neighbours, outlining buried features that would otherwise be invisible at ground level. The northern arc of this particular enclosure is the most clearly defined portion in that photograph, and it turns out to have had a longer afterlife in the landscape than the rest. Both the first edition Ordnance Survey six-inch map of 1839 and the 1948 revision record this northern stretch as a curvilinear field boundary, with the earlier map showing smaller subdivided fields contained within it. That a curving prehistoric or early medieval boundary should quietly persist as a property line for well over a century, and probably longer, is not unusual in Ireland, but it is a reminder of how stubbornly the logic of old enclosures can shape working farmland. The monument does not stand alone either. Three further enclosures, also visible as cropmarks in the same 1971 photograph, lie within roughly two hundred metres in the surrounding tillage, suggesting this corner of Kilkenny was once a more densely organised landscape than the present fields suggest.