Some ancient monuments announce themselves with standing stones or visible earthworks. This one exists, for now, almost entirely as a shadow in a satellite photograph. At Pollardstown in County Kildare, a circular cropmark was identified in a 2009 Google Earth image, showing the outline of a fosse, a defensive or enclosing ditch, describing a ring roughly eighteen metres across in what is otherwise level pasture. The pattern is consistent with a ring barrow, a low prehistoric burial mound typically surrounded by a circular ditch and sometimes an outer bank, common across Ireland from the Bronze Age onward. No excavation has confirmed what lies beneath, and the landscape around it has been heavily altered by sand and gravel extraction, which makes the survival of any sub-surface remains uncertain.

The identification was made through aerial and satellite observation rather than ground survey, a method that has become increasingly useful for detecting sites whose surface traces have been ploughed or otherwise levelled away. Cropmarks appear where buried features such as ditches or banks affect how vegetation grows above them, producing variations in colour or height that become legible from altitude, particularly in dry summers when grasses over buried ditches stay greener longer due to retained moisture. The Pollardstown example was flagged through personal communication with D. Brennan in March 2015. Whether the cropmark represents a genuine prehistoric funerary monument or some later feature remains, at this point, an open question.