Precambrian periods which were uplifted during the later Caledonian Orogeny. Smaller formations of Lewisian gneiss in the northwest are up to 3 billion years old. The overlying rocks of the Torridon Sandstone form mountains 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 is formed along a transform fault which divides the Grampian Mountains to the southeast from the Northwest Highlands. The entire region was covered by ice sheets during the Pleistocene ice ages, save perhaps for a few nunataks. The complex geomorphology includes incised valleys and lochs carved by the action of mountain streams and ice, and a topography of irregularly distributed mountains whose summits have similar heights above sea-level, but whose bases depend upon the amount of denudation to which the plateau has been subjected in various places. Climate The region is much warmer than other areas at similar latitudes (such as Kamchatka in Russia, or Labrador in Canada) because of the Gulf Stream making it cool, damp and temperate. The Köppen climate classification is “Cfb” at low altitudes, then becoming “Cfc”, “Dfc” and “ET” at higher altitudes. Places of interest An Teallach Aonach Mòr (Nevis Range ski centre) Arrochar Alps Balmoral Castle Balquhidder Battlefield of Culloden Beinn Alligin Beinn Eighe Ben Cruachan hydro-electric power station Ben Lomond Ben Macdui (second highest mountain in Scotland and UK) Ben Nevis (highest mountain in Scotland and UK) Cairngorms National Park Cairngorm Ski centre near Aviemore Cairngorm Mountains Caledonian Canal Cape Wrath Carrick Castle Castle Stalker Castle Tioram Chanonry Point Conic Hill Culloden Moor Dunadd Duart Castle Durness Eilean Donan Fingal's Cave (Staffa) Fort George Glen Coe Glen Etive Glen Kinglas Glen Lyon Glen Orchy Glenshee Ski Centre Glen Shiel Glen Spean Glenfinnan (and its railway station and viaduct) Grampian Mountains Hebrides Highland Folk Museum – The first open-air museum in the UK. Highland Wildlife Park Inveraray Castle Inveraray Jail