In a field in the townland of Oldtown, in the Bennett area of County Limerick, a circular feature roughly eight metres in diameter betrays itself only from above, showing up as a cropmark in satellite imagery. What lies beneath is interpreted as a possible ditch-barrow, a type of burial monument in which a central mound or grave is enclosed by a surrounding ditch, the whole forming a roughly circular plan. The ditch itself is long since silted and levelled, but the variation in soil moisture and crop growth it creates means that, under the right conditions, it briefly reappears as a ghostly outline in a green or golden field.

Cropmarks of this kind appear when buried features, such as ditches or pits, retain more moisture than the surrounding subsoil, causing the vegetation above them to grow taller or stay greener for longer during dry spells. Conversely, buried walls or compacted surfaces can create parch marks where crops fail or dry out early. The feature at Oldtown was identified in a Google Earth photograph taken on 25 March 2017, and the record was compiled by Caimin O'Brien, drawing on details provided by Jean-Charles Caillère, with the entry uploaded in January 2022. Ditch-barrows are a recognised class of funerary monument associated broadly with prehistoric burial practice in Ireland, though without ground survey or excavation it is not possible to say more about the date or character of this particular example. The cautious designation of "possible" in the record reflects how much remains uncertain when the only evidence is a faint ring seen from space.

Because the site exists primarily as a subsurface anomaly, there is nothing to see at ground level in ordinary conditions. The townland of Oldtown lies in rural County Limerick, and the field in question is agricultural land, so access would require the landowner's permission. Those with an interest in landscape archaeology might find it worthwhile to examine the area using Google Earth or the relevant aerial photography archives, where the March 2017 image offers the clearest view of the cropmark. The feature is best appreciated in that context, as a reminder that the Irish landscape holds a great deal of archaeology that has never been formally excavated and may never be, surviving only as a fleeting pattern in the grass.