This is a midden, a term for an ancient refuse deposit, typically composed of shellfish remains, animal bone, ash, and discarded domestic material, and the ones archaeologists find along Irish coastlines are often the clearest evidence we have that a particular stretch of shore was regularly used, cooked upon, and lived beside.

At Rusheens, the midden layer sits roughly 0.7 to 1 metre below the present sodline and about 2 metres above the base of the scarp, which gives some sense of how much the landscape has shifted since it was formed. The deposit itself extends approximately 6 metres in length and between 15 and 20 centimetres in depth, a relatively thin but coherent layer of oyster shells set within a dark brown and grey sandy soil that appears to contain some burnt stone, suggesting cooking or hearth activity nearby. The scarp in which it sits has been cut by erosion, exposing the deposit in cross-section, though vegetation partly obscures the face. No date has been established for the deposit, but middens of this kind along the Irish Atlantic coast range from prehistoric to early modern in origin, and the presence of burnt stone alongside shellfish is a combination found in sites across a very wide chronological span.