At Coolnagoppoge in south-west Kerry, the remnants of an ancient field system emerge from the ground in interrupted lines, collapsed stone walls no more than about half a metre high and sixty centimetres thick, pushing through the bog at intervals like the outline of something half-remembered. What they describe, taken together, is a substantial agricultural landscape: the whole system covers an area of roughly 270 metres by 230 metres across a north-west-facing slope of rough hill pasture.

What makes the site particularly interesting is the character of the walls themselves. Rather than the straight divisions typical of later planned enclosures, the boundaries here are mainly curvilinear, bending and curving to produce fields of many different shapes and sizes. This irregularity is often associated with early medieval or prehistoric land management, when field boundaries tended to follow the natural contours of the ground rather than impose a geometric grid upon them. The bog that has gradually overwhelmed the site is, paradoxically, part of why anything survives at all; peat accumulation can preserve stone and organic material that would otherwise disappear entirely, sealing earlier landscapes beneath layers of slowly compacted vegetation.