Lyell, << LY uhl, >> Sir Charles (1797-1875), was a British geologist whose writings established uniformitarianism as the basis of modern geology. Uniformitarianism is the theory that the gradual processes shaping the earth today, such as erosion, also formed the earth’s features in the past. James Hutton, a Scottish geologist, had introduced this theory in 1785. In Lyell’s day, however, most scientists still believed the earth had been shaped by rare and sudden events that were unique to the past.
Lyell convincingly set forth the theory of uniformitarianism in his three-volume work Principles of Geology (1830-1833). He stated that most of the earth’s structural features could be explained as the result of constantly occurring processes over millions of years. Lyell supported his theory by analyzing the long-term effect of observable events, such as the erosion of land by rivers. Lyell was born on Nov. 14, 1797, at Kinnordy, near Kirriemuir, Scotland. He died on Feb. 22, 1875.