This one, in a field of reclaimed pasture in County Limerick, is far more ambiguous. What may or may not be an earthwork near Ballincolloo exists primarily as a pattern of cropmarks, those faint discolourations in grass or grain that appear from the air when buried features alter how moisture and nutrients reach the surface above them. The trouble is that nobody is quite sure what lies beneath, or whether anything significant lies there at all.

The site came to attention in November 1984, when aerial photographs were taken at a scale of 1:10,000 during survey work associated with a Bord Gáis Éireann gas pipeline. Examination of those images revealed irregular-shaped cropmarks in reclaimed pasture roughly 30 metres west of the Morningstar River, which marks the townland boundary with Baggotstown West. The area sits immediately south of where Ballincolloo House once stood, the house itself now levelled. The cropmarks have since been visible on Ordnance Survey Ireland orthophotographs taken between 2005 and 2012, and on Google Earth imagery, which offers some reassurance that they are not a photographic artefact. However, the site does not appear on any OSi historic maps, and those compiling the record have noted the uncertainty plainly: the marks could represent an archaeological earthwork of some age, or they could simply be the traces of old drainage ditches, which are common in reclaimed pasture and leave very similar signatures from above. Antiquity, in this case, is considered doubtful.

There is nothing to see at ground level, which makes this less a place to visit than a place to think about. The landscape around the Morningstar River in this part of Limerick is flat, agricultural, and largely unremarkable to the casual eye, which is precisely what makes the aerial evidence interesting. If you are the sort of person who finds meaning in what is not quite there, the Google Earth orthoimage attached to the site record compiled by Fiona Rooney offers a quiet few minutes of squinting and speculation. The cropmarks are irregular, which is itself a clue of sorts; archaeological features like ringforts tend toward more regular geometry, while drainage works follow the logic of water and gradient rather than enclosure.