The rath at Ballybrian in County Galway does the opposite. Set in low-lying grassland, it has retreated so thoroughly into the earth that much of its defining bank has left no surface trace at all, surviving only as a partial arc across the southern and eastern sides.

A rath is a type of ringfort, a roughly circular enclosure defined by an earthen bank and, often, an outer ditch known as a fosse. These were the farmsteads of early medieval Ireland, occupied broadly between the fifth and twelfth centuries, and they survive in their thousands across the country, though in wildly varying states of preservation. At Ballybrian the site measures approximately 42 metres in diameter, which falls within the typical range. The bank that once defined it is now invisible from the west through the north to the north-northeast, and only slight traces of the external fosse remain, visible from the southeast around through south to southwest. What can be made out is, in essence, less than half the original circuit.