Skye that requires technical climbing skills to reach the summit. These hills make demands of the hill walker that exceed any others found in Scotland and a full traverse of the Cuillin ridge may take 15–20 hours. The Red Hills (Gaelic: ) to the south are also known as the Red Cuillin. They are mainly composed of granite that has weathered into more rounded hills with many long scree slopes on their flanks. The highest point of these hills is Glamaig, one of only two Corbetts on Skye. The northern peninsula of Trotternish is underlain by basalt, which provides relatively rich
Rùm Torridonian sandstone and shales resting on Lewisian gneiss. Two of the Cuillin are classified as Corbetts: Askival and Ainshval, (Old Norse for "mountain of the ash trees" and "hill of the strongholds" respectively) and Rùm is the smallest Scottish island to have a summit above . Other hills include Hallival, Trollaval ('mountain of the trolls'), Barkeval, and Sgurr nan Gillean (Gaelic: "peak of the young men") in the Cuillin and Ard Nev, Orval, Sròn an t-Saighdeir and Bloodstone Hill in the west. It is likely that only the higher peaks remained above the Pleistocene ice sheets as nunataks. Hallival and