GEIKIE, SIR ARCHIBALD (1835-1924), Scottish geolo gist, was born at Edinburgh on Dec. 28, 1835. He was educated at the high school and university of Edinburgh, and in 1855 was appointed an assistant on the Geological survey. His ability at once attracted the notice of his chief, Sir Roderick Murchison, with whom some of his earliest work was done on the complicated regions of the Highland schists; the small geological map of Scotland published in 1862 was their joint work, and a larger map was issued by Geikie in 1892. In 1863 he published his essay "On the Phenomena of the Glacial Drift of Scotland" (Trans. Geol. Soc. Glasgow) in which the effects of ice action in that country were for the first time clearly and connectedly delineated. His Scenery of Scotland (1865; 3rd ed., 1901), was, he claimed, "the first attempt to elucidate in some detail the history of the topog raphy of a country." In the same year he was elected F.R.S. At this time the Edinburgh school of geologists—prominent among them Sir Andrew Ramsay, with his Physical Geology and Geog raphy of Great Britain—were maintaining the supreme importance of denudation in the configuration of land-surfaces, and partic ularly the erosion of valleys by the action of running water. Geikie's book, based on extensive personal knowledge of the country, was an able contribution to the doctrines of the Edin burgh school, of which he himself soon began to rank as one of the leaders.
In 1867, when a separate branch of the Geological Survey was established for Scotland, he was appointed director. He was the first holder (1871) of the Murchison professorship of geology and mineralogy at Edinburgh. These two appointments he held till 1881, when he succeeded Andrew Ramsay in the joint offices of director-general of the Geological Survey of the United King dom and director of the museum of practical geology, London, from which he retired in February 1901. A feature of his tenure of office was the impetus given to microscopic petrography, a branch of geology to which he had devoted special study, by a splendid collection of sections of British rocks. Later he wrote two important and interesting Survey Memoirs, The Geology of Central and Western Fife and Kinross (19oo), and The Geology of Eastern Fife 0902).
In 1871 Geikie brought before the Geological Society of Lon don an outline of the Tertiary volcanic history of Britain. He travelled not only throughout Europe, but in western America to examine volcanic formations. While the canyons of the Colorado confirmed his long-standing views on erosion, the eruptive regions of Wyoming, Montana and Utah supplied him with valuable data in explanation of volcanic phenomena. The results of his further researches were given in his paper on "The History of Volcanic Action during the Tertiary Period in the British Isles," Trans. Roy. Soc. Edin. (1888). His mature views on volcanic geology were stated in his presidential addresses to the Geological Society in 1891 and 1892, and afterwards in his book, The Ancient Vol canoes of Great Britain (1897) . Other results of his travels are collected in his Geological Sketches at Home and Abroad (1882).
Geikie was president of the British Association in 1892 and of the Royal Society in 1909 ; he received the Order of Merit in 1914. He died near Haslemere, Surrey, on Nov. 1 o, 1924. His experience as a field geologist resulted in an admirable text-book, Outlines of Field Geology (5th ed. 1900) . His Text-Book (1882, 4th ed. I 903 ), and Class-Book of geology are standard works.