page_title: Knockan Crag
section_title: Flora and fauna
hierarchical_section_title: Knockan Crag / Flora and fauna
caption_attribution_description: English: Knockan Crag (Northwest Highlands, Scotland, UK) Deutsch: Geopark Knockan Crag (Northwest Highlands, Schottland, Vereinigtes Königreich)
context_page_description: 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'. The argument was primarily between Roderick Murchison and Archibald Geikie on the one hand and James Nicol and Charles Lapworth on the other. Murchison and Geikie believed the sequence was wrong and that the Moine schists must be the younger rocks. The controversy was finally resolved by the work of Ben Peach and John Horne whose 1907 paper on the subject remains a classic text. Peach and Horne demonstrated that the situation resulted from the action of a thrust fault - this being the first to be discovered anywhere in the world. The older rocks had been moved some 70 kilometres to the west over the top of the younger rocks due to tectonic action.
context_section_description: The plantlife of the area is highly influenced by its underlying geology. The soils formed on areas of limestone, fucoid beds and salterella grits are much richer than those on Moine schists. The lime-rich areas consequently support a richer vegetation, including plants such as mountain avens and rock sedge, whilst areas underlain by Moine schists tend to consist of wet heath and blanket bog. The transition between the two vegetation patterns is especially marked on the plateau above the crags, where there are small limestone knolls separated by peat-filled areas.
  Bird species found at Knockan Crag include kestrel, raven and ring ouzel, along with song birds such as dunnock, wren, stonechat and meadow pipit. Red- and black-throated divers visit nearby Lochan an Ais during the winter and spring, and so can be observed from the crag. Red deer regularly cross through the site.
caption: Cotton grass at Knockan Crag
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