It is easy to miss: a layer barely four to five centimetres thick, running just over half a metre in length, set into a scarp about a metre and a third high. This is a midden, a shell midden specifically, which is what archaeologists call the accumulated refuse of people who gathered and ate shellfish over a period of time. The shells are fragmentary, suggesting long burial and compression, and among them a single periwinkle shell was recorded, a small anomaly in an otherwise cockle-dominated deposit.

The scarp itself forms the land edge along the shoreline, and the midden sits exposed in cross-section where erosion has cut through it, offering a accidental window into the deposit rather than anything excavated deliberately. The lower portions of the bank are colonised by bright-green algae, which may be obscuring more of the deposit below. A second midden lies just twenty-five metres further south, visible in the same scarp face, which raises the possibility that this stretch of riverbank once saw repeated or sustained shellfish processing. About a hundred metres to the south stands Rosserk Abbey, a Franciscan friary founded in the fifteenth century and one of the better-preserved examples of its kind in Connacht. Whether there is any connection between the middens and the abbey's community is not recorded, though the proximity is difficult to ignore entirely.