In a field near Tipperkevin in County Kildare, there is a circle that nobody dug out and nobody has yet excavated. It shows up only from the air, a faint ring roughly twelve metres across, made visible not by any surviving earthwork but by the differential growth of crops above buried soil. This is a cropmark, a phenomenon in which the disturbed ground of an ancient ditch retains more moisture than the surrounding soil, causing the plants above it to grow taller and greener, outlining a shape that is otherwise completely invisible at ground level.

The ring-ditch form is well known in Irish and broader European prehistory. Such features are typically the remains of circular ditches dug around a burial or monument, sometimes enclosing a mound that has since been ploughed flat, sometimes surrounding nothing more than a grave. They range in date from the Neolithic through to the early medieval period, and without excavation it is rarely possible to say which era a particular example belongs to. This one at Tipperkevin, approximately twelve metres in diameter, was identified from Google Earth aerial imagery captured on 28 June 2018, with the record compiled by Caimin O'Brien on the basis of details provided by Jean-Charles Caillère. The summer date of the imagery is no accident; cropmarks tend to appear most clearly during dry spells in late June and July, when water stress in the growing plants amplifies the colour difference between disturbed and undisturbed ground.