Knockan Crag National Nature Reserve

Knockan Crag lies within the North West Highlands Geopark in the Assynt region of Scotland 21 kilometres north of Ullapool. During the nineteenth century Knockan Crag became the subject of much debate when geologists noted that the Moine schists at the top of the crag appeared to be older than the Cambrian and Ordovician rocks such as Durness limestone lower down. Disagreements over the processes that could have caused this to occur were referred to at the time as the "Highlands Controversy".