Andrew Crombie Ramsay (1814-1891) was a geologist who developed his theories based on field work undertaken in Wales in the period 1848-1851. In 1850 he spent a few days at the home of James Williams, rector of Llanfair-yng-Nghornwy, whose daughter Ramsay married in 1852. They honeymooned in Europe, “enabling Ramsay to see glaciers and glacial phenomena at first hand, as well as the contorted alpine rocks” (ODNB). The present work of comparative geology devotes its opening section to the Aar glacier in Switzerland, the remainder to evidence for glacial action in Wales.