Editing Great Cumbrae (section)

==Geology==
[[File:Crocodile rock.jpg|thumb|upright=1.1|left|Crocodile Rock, Millport]]
The island is formed largely from [[sandstone]]s and [[mudstone]]s of late [[Devonian]] and early [[Carboniferous]] age. This [[sedimentary rock|sedimentary bedrock]] is cut by numerous northeast–southwest aligned [[dike (geology)|igneous dykes]] intruded during the Carboniferous period. Further dykes were intruded during the [[Palaeogene]] period, cutting across the earlier ones in a north–south to NNW-SSE in orientation.  One of the latter is responsible for the 10m high roadside rock formation known as Lion Rock in the southeast of the island.<ref>{{cite web| url = http://www.millport.org/lion-rock/| url-status = dead| archive-url = https://web.archive.org/web/20150801165511/http://www.millport.org/lion-rock/| archive-date = 2015-08-01| title = Lion Rock}}</ref> Several [[fault (geology)|geological faults]] cut both the [[country rock]] and the dykes, the most significant being the north–south aligned Kames Bay Fault which extends from White Bay in the north to the bay from which it derives its name in the south.

The youngest sedimentary rocks are the sandstones forming 'The Eileans' in Millport Bay whilst the Kelly Burn Sandstone is the oldest. In [[stratigraphy|stratigraphical order]] (i.e. youngest at the top), the sequence is:

*[[Inverclyde Group]]
**Clyde Sandstone Formation
***Eileans Sandstone Member
***Millport Cornstones Member
**Ballagan Formation
**Kinnesswood Formation
***Foulport Sandstone Member
***Doughend Sandstone Member
*[[Stratheden Group]]
**Kelly Burn Sandstone Formation

The Doughend Sandstone (named from the westernmost reach of the island) [[unconformity|unconformably overlies]] the Kelly Burn Sandstone; both are of late Devonian age whilst the rest of the sequence is of Carboniferous age.

Various of the rock formations have become popular with tourists, including Crocodile Rock, Indian's Face, Lion Rock and Queen Victoria's Face. Several have been enhanced with colourful paint.

A [[raised beach]] is developed around almost the whole of the island at about {{Convert|8|m}} above current sea level. Vegetated spreads of sand, shingle and boulders occur locally across this platform. Wider in the west, it has been exploited by the B896 coastal road. The island's highest waterfall, Horse Falls, plunges over the old sea cliffs at Bell Bay. A higher raised beach is covered by marine deposits inland of Millport Bay and in the northeast of the island. Inland are traces of [[till]] deposited by the glacial ice which over-ran the island during the last ice age. Small areas of [[peat]], [[alluvium]] and blown sand are also present in places.<ref>British Geological Survey 2008. ''Dunoon and Millport'', Scotland sheet 29E with part of 21E. Bedrock and superficial deposits . 1:50,000. (Keyworth, Nottingham: BGS)</ref>