South West England development because of its environmental importance, which contributes to the region's attractiveness to tourists and residents. Geologically the region is divided into the largely igneous and metamorphic west and sedimentary east, the dividing line slightly to the west of the River Exe. Cornwall and West Devon's landscape is of rocky coastline and high moorland, notably at Bodmin Moor and Dartmoor. These are due to the granite and slate that underlie the area. The highest point of the region is High Willhays, at , on Dartmoor. In North Devon the slates of the west and limestones of the east meet at
High Willhays summits in England south of Kinder Scout in the Peak District to rise above , apart from Black Mountain on the Welsh border. Before Ordnance Survey measured accurately the heights of High Willhays and Yes Tor many people believed Yes Tor was the higher of the two, and it was only the local farmers and moormen that believed the contrary. However, the first topographical survey of the area carried out by Ordnance Survey suggested that High Willhays was higher, although the difference has now been measured at just . William Crossing stated that High Willhays was the highest point in