A. Geikie & W. Gunn 
Memoirs of the Geological Survey Scotland [PDF ebook] 
The Geology of North Arran, South Bute, and the Cumbraes, With Parts of Ayrshire and Kintyre (Sheet 21, Scotland)

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. Considerably more than one half (about five eighths) of the area of this sheet is occupied by sea – the Firth of Clyde and its branches and the land amounts to only about 161 square miles. The land area belongs to three different counties, and consists Of no less than nine separate portions – seven of them being islands or parts of islands, and the other two belong to the mainland of Scotland.