On reclaimed pasture at Dollas Upper, a shallow fosse, that is, a ditch, once defined the perimeter of an enclosed circular space roughly 37 metres across. The ditch is no longer visible at ground level, but under the right seasonal conditions, the soil and crop growth above it betray its presence. The result is a cropmark, a faint but legible ghost of a structure that has otherwise entirely vanished into the landscape.

Cropmarks form when buried features such as ditches or walls affect the moisture and depth of soil above them. Crops growing over a filled-in ditch tend to grow taller and greener, while those over buried stonework may be stunted. Seen from aerial photography, these subtle variations in colour and height trace out shapes that are otherwise invisible. This particular enclosure at Dollas Upper was identified from an Ordnance Survey Ireland orthophoto taken between 2005 and 2012, and confirmed by a Digital Globe orthoimage from 2011 to 2013. The record was compiled by Caimin O'Brien, drawing on details provided by Edmond O'Donovan, and uploaded in September 2020. What the images show is a roughly circular area, approximately 37 metres north to south, defined by that shallow fosse. Notably, a ringfort already recorded in the national monuments register sits just 83 metres to the south-west. Ringforts, which are enclosed farmsteads typically dating from the early medieval period, are common across Ireland, and the proximity of this enclosure to one raises the question of whether the two features are related, though that remains unresolved.

There is nothing to see at ground level, and that is rather the point. Visitors with an interest in landscape archaeology can cross-reference the site using the National Monuments Service mapping portal, where the record sits alongside the nearby ringfort. The area is reclaimed pasture, so access will depend on landowner permission. The cropmark itself would only have been apparent from the air during dry summer conditions, when differential crop growth is most pronounced. Anyone hoping to understand what they are looking at on the ground will find the aerial images, referenced in the monument record, far more instructive than the field itself.