Cuillin criteria for these hill listings. Cuillin The Cuillin ( or ') is a range of rocky mountains located on the Isle of Skye in Scotland. The main Cuillin ridge is also known as the Black Cuillin to distinguish it from the Red Cuillin (', known locally as Red Hills), which lie to the east of Glen Sligachan. The peaks of the Black Cuillin are mainly composed of gabbro, a very rough igneous rock which provides a superb grip for mountaineers; and basalt, which can be very slippery when wet. The rocks forming the ridge of the Black Cuillin (and outliers
Cheviot Hills they are separated from the Cheviot Hills by the Tyne Gap, part of which lies within the southern extent of the Northumberland National Park. The Cheviot Hills are primarily associated with geological activity from approximately 480 to 360 million years ago, when the continents of Avalonia and Laurentia collided, resulting in extensive volcanic activity (the Caledonian orogeny) which created a granite outcrop surrounded by lava flows. The area enjoys a general right to roam under both the English Countryside and Rights of Way Act 2000 and the Scottish Land Reform (Scotland) Act 2003. The Southern Cheviots include the Otterburn Training