Director of the British Geological Survey from 1881 to 1901, Geikie made studies of glacial and fluvial erosion, and attempted to calculate the age of the Earth from rates of denudation. This led to conflict with Kelvin. Geikie was also one of the first historians of geology, stressing in his Founders of Geology (1897, 1905) the importance of the work of his fellow Scotsman Hutton.