Scottish Highlands in the Torridon Hills such as Liathach and Beinn Eighe in Wester Ross. These foundations are interspersed with many igneous intrusions of a more recent age, the remnants of which have formed mountain massifs such as the Cairngorms and the Cuillin of Skye. A significant exception to the above are the fossil-bearing beds of Old Red Sandstone found principally along the Moray Firth coast and partially down the Highland Boundary Fault. The Jurassic beds found in isolated locations on Skye and Applecross reflect the complex underlying geology. They are the original source of much North Sea oil. The Great Glen
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