Somewhere beneath the farmland near Kilkea in County Kildare, a set of ancient field boundaries lies invisible at ground level, detectable only from the air. The fields themselves vanished long ago, but their outlines persisted as cropmarks, the subtle discolouration that appears in growing crops above buried features, caused by differences in soil moisture and nutrients where old ditches and banks once ran. In this case, the boundaries took the form of fosses, a term for shallow ditches dug to demarcate land, and their geometry was clear enough to be photographed from an aircraft.

The evidence comes from aerial photography, specifically a photograph catalogued as CUCAP AVM 7, which revealed the cropmark outline of a small field system defined by these fosses. What makes the site more interesting is the company it keeps. Two other small field systems and a circular enclosure lie in the immediate vicinity, suggesting that this corner of Kildare preserves the ghostly imprint of a broader pattern of land use, possibly from the prehistoric or early medieval period, when small enclosed fields were common across the Irish landscape. The features were visible again on a later aerial photograph taken in 1989, confirming they were no passing trick of the light or a single season's anomaly.

No excavation data is available to date the field system precisely, and the ground surface today gives nothing away. The significance of the site lies almost entirely in what the sky reveals, a reminder that some of the most informative archaeological observations in Ireland have been made not by digging but by looking down at the right moment, in the right conditions, when a dry summer draws the past up through the grass.