The Scottish geologist Andrew Crombie Ramsay (1814 91), best remembered for his work on glaciation, made his name with this study, which originated in holiday visits to Arran. Encouraged by John Nichol of Glasgow University, Ramsay had prepared a geological map of the island for the British Association's visit in 1839, and was to have led a field excursion and lectured to the delegates there, but missed the boat. Nichol arranged for Ramsay's work to be published the following year. It attracted the attention of Roderick Murchison, who found him employment with the Geological Survey, and...