What is Staffa?
[[File:STAFFA ISLAND - aerial view.gif|right|thumb|230px|Aerial view of Staffa, with The Colonnade in the foreground and Am Buchaille to the right]] [[File:Staffa beside 14624.JPG|thumb|[[Basalt]] columns: Am Buchaille on Staffa]] [[File:Staffa04.jpg|right|thumb|230px|Basalt columns inside [[Fingal's Cave]]]] '''Staffa''' is an island in the [[Inner Hebrides]] off the north-west of [[Scotland]]. It is famous for [[Fingal's Cave]] and other examples of [[basalt]] columns. No-one lives there. The islands became part of the Kingdom of Mann and the Isles, the ''Suðreyjar'' kingdom of the [[Norse]]. The Norsemen ruled for over 400 years until sovereignty was transferred to Scotland by the [[Treaty of Perth]] in 1266. The islands were then held by the [[Clan]]s MacLeod and MacDonald, but Staffa was not regularly inhabited. == Geology == This small island is entirely of [[volcanic]] origin. It consists of a basement of [[tuff]], underneath colonnades of a black fine-grained [[Tertiary]] [[basalt]], overlying which is a third layer of basalt [[lava]]. Slow cooling of the second layer of basalt resulted in an extraordinary pattern of [[hexagonal]] [[column]]s which form the faces and walls of the principal caves.<ref name=Smith>Haswell-Smith, Hamish. 2004. ''The Scottish Islands''. Edinburgh. Canongate</ref> The lava contracted as it cooled and solidified into columns, a process known as columnar jointing. The columns have three to eight sides, six being most common. The columns are also divided horizontally by cross joints.<ref>Mitchell, Colin and Mitchell, Patrick 2005. ''Landform and terrain: the physical geography of landscape'' Brailsford Press. {{ISBN|1904623565}} [http://www.brailsfordpress.com/chapters%201-3.pdf 3.pdf] {{Webarchive|url=https://web.archive.org/web/20080407142126/http://www.brailsfordpress.com/chapters%201-3.pdf |date=2008-04-07 }}</ref> Similar formations are found at the [[Giant's Causeway]] in [[Northern Ireland]], on the island of [[Ulva]] and Ardmeanach on the [[Isle of Mull]].<ref name=Kea