Editing Isle of Lewis (section)

== Geography and geology ==
[[File:Wfm lewis landsat.jpg|thumb|right|Satellite photograph of Lewis and Harris]]
Much of Lewis consists of mostly sandy beaches backed by dunes and [[machair]] on the Atlantic west coast, giving way to an expansive peat-covered plateau in the centre of the island. The eastern coastline is markedly more rugged and is mostly rocky cliffs broken by small coves and beaches. The more fertile nature of the eastern side led to the majority of the population settling there, including the largest settlement and only town, [[Stornoway]]. Aside from the village of [[Achmore, Lewis|Achmore]] in the centre of the island, all settlements are on the coast.<ref>Pankhurst R.J. & Mullin, J.M. (1991) ''Flora of the Outer Hebrides'', London: HMSO</ref>

[[File:UigLoch.jpg|thumb|left|Looking towards the uplands in the centre of the Island of Lewis]]Compared with Harris, Lewis is relatively flat, except in the south-west, where [[Mealaisbhal]], {{convert|574|m|ft|abbr=on}}, is the highest point, and in the south-east, where Beinn Mhor reaches {{convert|572|m|ft|abbr=on}}; but there are 16 high points exceeding {{convert|300|m|ft|abbr=on}} in height.<ref>[http://bubl.ac.uk/org/tacit/marilyns/region24.htm] {{webarchive|url=https://web.archive.org/web/20120222065105/http://bubl.ac.uk/org/tacit/marilyns/region24.htm|date=22 February 2012}}</ref> Southern Lewis also has a large number of freshwater lochs compared to the north of the island.

[[South Lewis, Harris and North Uist NSA|South Lewis, Harris and North Uist]] together comprise a [[National Scenic Area (Scotland)|National Scenic Area]]. There are four geographical [[Sites of Special Scientific Interest]] (SSSI) on Lewis – Glen Valtos, Cnoc a' Chapuill, Port of Ness and Tolsta Head.<ref>[http://www.snh.gov.uk/protecting-scotlands-nature/protected-areas/national-designations/nsa/ "National Scenic Areas"] {{webarchive|url=https://web.archive.org/web/20170311014235/http://www.snh.gov.uk/protecting-scotlands-nature/protected-areas/national-designations/nsa/ |date=11 March 2017 }}. SNH. Retrieved 30 March 2011.</ref><ref name="snhsitelink">{{Cite web|url=http://gateway.snh.gov.uk/natural-spaces/|title=Natural Spaces - Scottish Natural Heritage|website=gateway.snh.gov.uk}}</ref>

The coastline is severely indented, creating a number of large sea lochs, such as Lochs [[Loch Resort|Resort]] and [[Loch Seaforth|Seaforth]], which form part of the border with Harris, [[Loch Roag]], which surrounds the island of Great Bernera, and [[Loch Erisort]]. The principal capes are the [[Butt of Lewis]], in the extreme north, with hundred foot (30 m) cliffs (the high point is {{convert|142|ft|m|abbr=on}} high)<ref>{{Cite web|url=https://digital.nls.uk/gallery/|title=Digital gallery - National Library of Scotland|website=digital.nls.uk}}</ref> and crowned with a lighthouse, the light of which is visible for {{convert|19|mi}}; Tolsta Head, Tiumpan Head and Cabag Head, on the east; Renish Point, in the extreme south; and, on the west, Toe Head and Gallon Head.<ref name="1911 Lewis with Harris">{{cite EB1911 |wstitle=Lewis-with-Harris |volume=16 |pages=525–526}}</ref> The largest island associated with Lewis is Bernera or [[Great Bernera]] in the district of [[Uig, Lewis|Uig]] and is linked to the mainland of Lewis by a bridge opened in 1953.

=== Geology ===
[[File:Lewis abandoned.jpg|thumb|right|Abandoned house and croft in SW Lewis, with exposed gneiss visible.]]
The geology of Lewis is dominated by the [[metamorphic rocks|metamorphic]] [[gneiss]]es of the eponymous [[Lewisian complex]].<ref>{{cite book|last1=Park|first1=R.G.|last2=Stewart|first2=A.D.|last3=Wright|first3=D.T.|editor=Trewin N.H.|title=The Geology of Scotland  |chapter-url=https://books.google.com/books?id=ObdepEp9r7kC&pg=PA45|year=2003|publisher=Geological Society|location=London|isbn=978-1-86239-126-0|pages=45–61|chapter=3. The Hebridean terrane}}</ref> Exceptions are a patch of [[granite]] near [[Carloway]], small bands of intrusive [[basalt]] at Gress and in Eye Peninsula and some [[sandstone]] at Stornoway, Tong, Vatisker and Carloway, which was originally thought to be [[Torridonian]],<ref name="1911 Lewis with Harris"/> but is now considered more likely to be [[Permian|Permo]]-[[Triassic]] in age.<ref>{{cite journal|url=http://jgs.geoscienceworld.org/content/131/2/183|title=Sedimentation and tectonism (?Permo-Triassic) on the margin of the North Minch Basin, Lewis|journal=Journal of the Geological Society|first1=Ronald J.|last1=Steel|first2=Alan C.|last2=Wilson|date=1 April 1975|volume=131|issue=2|pages=183–200|via=jgs.geoscienceworld.org|doi=10.1144/gsjgs.131.2.0183|bibcode=1975JGSoc.131..183S|s2cid=129036870}}</ref>