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).
Skye at Waterstein Head. Oolitic loam provides good arable land in the main valley. Lochs Bracadale and Harport and the island of Wiay lie between Duirinish and Minginish, which includes the narrower defiles of Talisker and Glen Brittle and whose beaches are formed from black basaltic sands. Strathaird is a relatively small peninsula close to the Cuillin hills with only a few crofting communities, the island of Soay lies offshore. The bedrock of Sleat in the south is Torridonian sandstone, which produces poor soils and boggy ground, although its lower elevations and relatively sheltered eastern shores enable a lush growth of