Maximum altitude of the Late Devensian ice sheet on the Isle of Rum

Dahl et al. (1996) have recently published a reconstruction of the upper surface of the last (Late Devensian) ice sheet on Skye. This shows that at its maximum thickness the ice surface descended from 750–870 m in the Cuillins to c. 450 m in north and NW Skye, and raises the possibility that the highest summits on the neighbouring island of Rum also escaped glaciation by the Late Devensian ice sheet, which is thought to have built up after c. 25 ka BP but to have retreated to the mountains of the Western Highlands by c. 13 ka BP (Sutherland 1991). We here present evidence for the upper limit of Late Devensian glaciation on Rum, and assess its wider significance. Evidence provided by striae, ice-moulded rock and erratics demonstrates that at the last glacial maximum ice from the Scottish mainland crossed Rum in a westerly direction, but was deflected northwards and southwards around mountains in the south of the island (Harker 1908; Peacock 1976; Le Coeur 1994; Fig. 1). Harker (1908) noted that erratics occur up to 550 m on Barkeval, and believed that ice had covered the highest summits, a view echoed by Ryder (1968) and Ryder and McCann (1971). However, Godard (1965) depicted nunataks on Rum above c. 570 m, an interpretation favoured by Le Coeur (1994) on the grounds that ice-moulded bedrock occurs only below this altitude, whereas rock pinnacles, protruding dykes and ‘couloirs de gelivation’ (frost-weathered gullies) occupy higher ground. Wilson (1969) demonstrated the presence . . .