Cuillin range. Cracks and fissures in the rock provided pathways for later magma intrusions, leading to dykes of basalt which are commonly seen across Skye. The Red Cuillin also have volcanic origins, being formed from a later intrusion of acidic, granitic rock. This granite was more uniformly eroded by wind and water than the gabbro and basalt, causing the red hills to have smoother outlines. The Cuillin provide classic examples of glacial topography and were the subject of an early published account by James Forbes in 1846 (who had become a fellow of the Royal Society of Edinburgh aged only nineteen).
Cuillin and magnetic abnormalities that make compass reading unreliable. The majority of scramblers heading on to the Black Cuillin do so via routes from Glenbrittle (where there is a campsite and a youth hostel) or Sligachan for the northern peaks: due to the remoteness of Loch Coruisk, which can only be reached by boat or a "c." 10 km walk from Elgol, routes starting from this side are less frequented. In addition to climbing individual peaks, there is the challenge of a full traverse of the main Black Cuillin ridge. Although only in length, the average traverse is likely to take