James D. Dana

James D. Dana (born February 12, 1813, Utica, New York, U.S.—died April 14, 1895, New Haven, Connecticut) was an American geologist, mineralogist, and naturalist who, in explorations of the South Pacific, the U.S. Northwest, Europe, and elsewhere, made important studies of mountain building, volcanic activity, sea life, and the origin and structure of continents and ocean basins.

Dana attended Charles Bartlett’s Academy and then entered Yale College as a sophomore in 1830. On graduation from Yale in 1833 he instructed midshipmen in mathematics on a U.S. Navy cruise to the Mediterranean; he returned to New Haven in 1836 as an assistant to his former teacher, Benjamin Silliman, professor of chemistry and mineralogy at Yale. Evidence of Dana’s great productive energy came at age 24 with the publication in 1837 of A System of Mineralogy, a work of 580 pages that has persisted through numerous editions.

In 1838 Dana joined a United States exploring expedition to the South Seas with Charles Wilkes; he served four years as a geologist and also was responsible for much of the zoological work. In 1844, two years after his return from that expedition, Dana married Henrietta Silliman, the daughter of his mentor at Yale, and settled in New Haven. Dana spent his intense energy largely on science. From 1844 to 1854, his most productive years, he published about 7,000 printed pages in addition to hundreds of plates, most of which he drew. His writings on the Wilkes expedition include four illustrated quarto volumes and numerous short papers.

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Exploration and Discovery

The main thrust of Dana’s effort was geological. Among his many publications were the text Manual of Mineralogy (1848) and three editions of A System of Mineralogy (1st ed., 1837), including a complete revision in which he founded a classification of minerals based on mathematics, physics, and chemistry. More significant to Dana’s impact on American geology during this decade was the start of his long association with the American Journal of Science, a leading organ of scientific inquiry founded by Benjamin Silliman. As an editor and contributor of critical reviews, original papers, and perceptive syntheses, Dana exerted a vitalizing influence on American geology. One of the best-informed men of science in his day, his concern with the physical processes that produced geologic phenomena led to brilliant generalizations on such fundamental questions as the formation of the physical features of the Earth, the origin and structure of continents and ocean basins, the nature of mountain building, and volcanic activity. From his own studies and his mastery of the works of other American and foreign geologists, Dana constructed a view of the Earth as a geologic unity developing through time. Adopting the theory of a contracting Earth cooling from a molten condition, he argued that the present continents mark areas that cooled first; subsequent contractions caused the intervening oceanic areas to subside. As settling oceanic crusts adapted periodically to a shrinking interior, pressure was exerted against continental margins causing upheaval of great mountain chains such as the Appalachians, Rockies, and Andes. Dana stressed the progressive change of the Earth’s physical features but at first was reluctant to accept the idea of the evolution of living things.

By the early 1850s Dana had attained international recognition and was corresponding with other outstanding scientists of his day, among them Asa Gray, noted American botanist; Louis Agassiz, Swiss-born naturalist and teacher at Harvard; and Charles Darwin. All had measurable influence on his thinking. Spurred by tentative proposals from Harvard for Dana’s services, friends at Yale established the Silliman Professorship of Natural History, which Dana accepted in 1856. But in 1859, the strain of his self-imposed overwork resulted in a physical breakdown from which he never fully recovered. During his remaining 35 years he was forced to live a secluded existence, largely withdrawn from the public. For a less modest man this would have been difficult, for many academic honours came to him during this period. Recognition included the presidencies of the American Association for the Advancement of Science and the Geological Society of America; he was also a founding member of the National Academy of Sciences.

Despite ill health Dana continued to publish: in 1862 his influential textbook, Manual of Geology (4 eds.); in 1864 A Text-book of Geology, a more elementary work; and in 1872 Corals and Coral Islands, which was the climax to his notable studies of coral reefs, begun on the Wilkes expedition. Dana investigated coral islands in greater detail than anyone before him, substantiating Darwin’s observation that atolls were evidence of subsidence of the ocean bottom. Reef-building corals, Dana independently concluded, lived only in shallow tropical waters on hard substrates, commonly forming fringing reefs about volcanic islands. Coral rock found at some depth on island flanks and atolls made only of reef rock indicated that extensive volcanic lands had disappeared beneath the Pacific leaving clusters of atolls to mark their former existence.

During his later years he wrestled with the challenge of organic evolution proposed by Darwin. Always a deeply religious man, Dana believed in the special creation of species, yet he was keenly aware of the intricate relationships between species and their environment. Darwin’s impressive argument, coupled with Dana’s own zoological knowledge, was persuasive in the end, however, and he adopted evolution theory in the last edition of his Manual. For Dana the natural and the divine had to be inseparable—all nature and the design of continual improvement of life that he read into it were a manifestation of the divine.

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During Dana’s lifetime, and largely under his leadership, American geology grew from a collection and classification of unrelated facts into a mature science.