Cuillin He partnered Louis Agassiz on his trip to Scotland in 1840 and although they subsequently argued, Forbes went on to publish other important papers on Alpine glaciers. In 1904 Alfred Harker published "The Tertiary Igneous Rocks of Skye", the first detailed scientific study of an extinct volcano. The Cuillin encompasses a wide range of habitats, changing with altitude. At the base there are conifer plantations, coastal woodlands and areas of heather moorland and rough grassland. The lower slopes are covered by various different types of bog, with grassland on the better-drained slopes that are found above 400 m. Higher up,
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