At Tullig in County Kerry, the working face of a cutaway bog has exposed a stretch of ancient field wall, its pale stones emerging from the dark peat like a line drawn by a hand that pre-dates written record. The wall runs roughly north to south, and where it is visible in the east-west turf face it extends about ten metres southward, standing just thirty centimetres high and roughly eighty centimetres thick. The stones, both large and small, have a notably white appearance, which is typical of material that has been sealed from light and air for a very long time.

Bogs preserve what farmland and pasture destroy. When a field wall is swallowed by encroaching peat, it can be held in near-perfect suspension for centuries or even millennia, the acidic, oxygen-poor conditions slowing decay to almost nothing. What has been cut away at Tullig gives only a partial view; a further sixteen metres of the same wall continues northward beneath the uncut bog, still buried and intact. The wall appears to rest on the base clay layer beneath the peat, which suggests it was built on open ground long before the bog began to form over it. This is a relict landscape, a fragment of a farming system that was operating when this part of south-west Kerry looked entirely different, before the gradual waterlogging that transforms open ground into bogland had even begun.