A shell midden is essentially a rubbish deposit, the accumulated cast-offs of shellfish meals over what may have been a long period of time. This one, seven metres long, just over three metres wide, and almost a metre high, sits partially beneath the rectangular graveyard wall itself, which means the wall was built over it at some point, or the midden crept outward to meet it. Either way, the two features have been quietly intertwined for some time.

The deposit is badly disturbed, but what survives tells a clear story about diet and local abundance. Around ninety per cent of the shells are cockle, with periwinkle and oyster making up roughly five per cent each. A section of the midden is visible about a metre southeast of the graveyard wall, giving some sense of its layered bulk. The site sits in the southwest corner of what was once a large ecclesiastical enclosure, though the enclosure itself is now poorly preserved. According to a personal communication from T. Coffey in 1994, this is one of two middens noted in the area; the second recorded midden has never been located.