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 ensure its protection from inappropriate development. The areas protected by the designation are considered to represent the type of scenic beauty "popularly associated with Scotland and for which it is renowned". The "Cuillin Hills National Scenic Area" covers 22,726 ha, of which 27,320 ha is on land, with a further 4594 ha being marine (i.e. below low tide level). Due to the rocky nature of the Cuillin they have historically been of little use for agriculture: this contrasts with the majority of the highlands, where the hills were used to provide seasonal grazing for cattle and sheep. Despite the lack