Not scattered shells, but several stone boxes of them, sealed and left inside the enclosure. That detail, reported by a researcher named Henry in 1957, is almost the strangest thing about this site on An Seanchnoc, a low hill above the Finglas river in south Kerry. Almost, because the structure itself has been so thoroughly altered over the centuries that it barely resembles what the earliest Ordnance Survey maps recorded.

A rath, or ringfort, is a roughly circular enclosed settlement, typically of early medieval date, defined by one or more earthen banks or stone walls. The example at An Seanchnoc was originally stone-built, its perimeter formed by drystone-faced walling, but most of that fabric has long since been replaced by ordinary field walling, leaving the enclosure with an irregular, lumpy outline that gives little away. Small portions of the original construction still survive: a section of the early walling remains visible at the north-east, and further remnants push up through the ground at the south, half-buried beneath the later wall. A single large upright slab on the western side, set at a right angle to the wall line, may mark where the entrance once stood. A low bank to the south-west is probably the result of generations of field clearance rather than any deliberate prehistoric feature. Heavy vegetation has made close inspection difficult.

The periwinkle story sits unverified in the record, passed on second-hand to Henry by someone who had been involved in removing stones from inside the enclosure. Stone boxes, sometimes called cist-like containers, are known from various Irish archaeological contexts, though their use here, filled with marine shells far from the coast, remains unexplained. Whether the shells had a ritual significance, were stored as food, or arrived by some more mundane process is unknown. It is the kind of detail that lodges in the mind long after the eroded outline of the earthwork itself has faded from memory.