On a gentle south-facing slope at An Inse Mhór in County Cork, that is precisely what has happened to a set of stone field boundaries whose curving lines trace a roughly rectangular area of around 150 metres east to west and 70 metres north to south. The walls, where visible, stand no more than 0.3 metres high and are about 0.6 metres thick, modest dimensions that nonetheless speak to a sustained and organised effort to divide and work this ground. Where the bog deepens in the level sections, the walls vanish entirely, absorbed into the peat.

These are relict field boundaries, meaning they were built, used, and eventually abandoned long enough ago that the landscape has since fundamentally changed around them. The surrounding ground is now rough hill grazing on bog, not the kind of terrain that would obviously invite the labour of wall-building. At some earlier period, conditions here were different, the land workable enough to justify dividing it into enclosures with carefully laid stone. The curvilinear form of the walls is worth noting: straight-sided, rectilinear field systems tend to be associated with later, more planned agricultural reorganisation, while curving boundaries often reflect an older tradition of working with the natural contours of the ground. Across the valley, the rocky outcrop of Carrignaspirroge provides a fixed point of reference, the kind of prominent feature that would have oriented anyone farming this hillside for generations.