AbstractActive stony earth circles occur on the less coarse cells of relict sorted nets developed in quartzite debris above 600m ASL on Muckish Mountain, north‐west Ireland. The earth circles are underlain by deformed and truncated podzolic soil horizons that resemble cryoturbations produced by differential frost heave of adjacent sediments. Grain‐size distributions indicate that the soils are frost‐susceptible and possess negative frost‐susceptibility gradients. This infrequent association of coarse quartzite debris and fine‐grained frost‐susceptible matrix probably arises from the weathering of thin inter‐bedded pelites (schists) within the quartzite. Recent activity may have been triggered by climatic deterioration during the Little Ice Age, although present climate on Muckish appears capable of maintaining the surface morphology of the stony earth circles. These features, along with forms described previously, suggest that most if not all upland areas in Ireland above 600‐700m ASL possess climatic conditions favouring frost‐relat