Emmons, Samuel Franklin

(b. Boston, Massachusetts, 29 March 1841; d. Washington, D.C., 28 March 1911)

geology, Mining.

Emmons was a descendant of Thomas Emmons, one of the founders of the Rhode Island Colony, who was “admitted to be an inhabitant of Boston” in 1648. His father was Nathaniel Henry Emmons, a highly respected and affluent Boston merchant engaged in the East India and China trade. His mother, Elizabeth Wales, was a descendant of Nathaniel Wales, who emigrated from Yorkshire to Boston in 1635. He was named for a great-grandfather on his father’s side, Samuel Franklin, a cousin of Benjamin Franklin.

During his boyhood Emmons attended private schools, including the Dixwell Latin School, where he had rigorous training in English composition and some instruction in physical geography and mapmaking, all of which stood him in good stead in later years. He entered Harvard College at the age of seventeen and graduated with an A.B. degree in 1861. The next five years were spent in Europe, climbing in the Alps in the summer of 1861 and then studying with private tutors in Paris to gain admission to the École Impériale des Mines, where he was a student during the academic years 1862–1863 and 1863–1864. He then enrolled in the Bergakademie at Freiberg, Saxony, where he remained until midsummer 1865, after which he visited many of the important European mining centers, finally returning to Boston from Rome in June 1866, at which time Harvard awarded him an A.M. degree.

In late 1866 and early 1867 the geological exploration of the fortieth parallel, under the direction of the chief of engineers, U.S. Army, was authorized by Congress and organized by Clarence King, who was chief geologist. Arnold Hague, who had become acquainted with Emmons when they were students at Freiberg, was appointed one of King’s assistant geologists. Through Hague’s influence King accepted Emmons as a volunteer assistant for the 1867 field season. The following winter Emmons received an official appointment as assistant geologist, a position he held until the completion of his reports in 1877, when he resigned to engage in cattle ranching in Wyoming. The U.S. Geological Survey was created by act of Congress on 3 March 1879. Clarence King was its first director, and one of his first official acts was to appoint Emmons as geologist in charge of the Rocky Mountain Division. Later he was placed in charge of the Division of Economic Geology, where he remained until his death.

Emmons was married three times: on 5 August 1876 to Waltha Anita Steeves of New York, from whom he was subsequently divorced; on 14 February 1889 to Sophie Dallas Markoe of Washington, who died on 19 June 1896; and on 4 August 1903 to Suzanne Earle Ogden-Jones of Dinard, France, who survived him. He left no children.

Emmons was active in many scientific organizations. He was a member of the National Academy of Sciences and its treasurer from 1902 to 1910. He was one of the founders of the Geological Society of America in 1888 and its president in 1903. Earlier he had helped to establish the Colorado Scientific Society and was its first president in 1882. Emmons was a member or fellow of the American Academy of Arts and Sciences, the American Philosophical Society, the American Association for the Advancement of Science, the Washington Academy of Sciences, the Geological Society of Washington (of which he was president for one term), and the American Institute of Mining Engineers, of which he was vice-president in 1882 and again in 1890 and 1891. When the International Geological Congress met in Washington in 1871, he was its general secretary, and at meetings in other countries in 1897, 1903, and 1910 he was one of its vice-presidents. Emmons became a fellow of the Geological Society of London in 1874 and later an honorary member of the Société Helvétique des Sciences Naturelles. Columbia and Harvard conferred honorary Sc.D. degrees upon him in 1909.

Although mining geology, especially the origin of ore deposits, was Emmons’ major interest, his contributions to regional and structural geology were notable. His assignment with the fortieth-parallel exploration involved the survey of an area, about 100 miles in width, extending from the Sierra Nevada to the Great Plains. Much of the region was then so little settled that detachments of the U.S. Army accompanied the field parties to protect them from hostile Indians. The report on this pioneer work (1877) promptly became a model for regional studies and was emulated by many geologists.

The directives for Emmons’ early work in the U.S. Geological Survey were conflicting. Most desirable from his point of view were the instructions to prepare a monograph on the region of Leadville, Colorado, at that time one of the most productive mining localities in the Rocky Mountains. But this was in 1879, and the Geological Survey had undertaken the collection of statistics on precious metals for the tenth census (1880). That task was also given to Emmons and G. F. Becker. With characteristic energy Emmons fulfilled both duties simultaneously. Volume XIII of the Tenth Census Reports, by Emmons and Becker, with its geological descriptions of mining regions, was published in 1885. A preliminary report on the geology and mining industry of the Leadville region was published in 1882 and the definitive monograph in 1886. This immediately attracted widespread attention and stimulated the investigation of the origin of ore deposits in other mining regions.

Emmons’ conclusion that the ores had been derived mainly from the intruded igneous rocks and deposited in adjacent sedimentary rocks by hot aqueous solutions led to the classification of many ore bodies all over the world as results of contact metamorphism. His suggestion that the hot aqueous solutions were of meteoric origin, heated at depth by contact with hot igneous rock, provoked long-continuing discussion, and in his later work he modified his original theory to include the idea that they were partly of magmatic origin. This development of Emmons’ concepts of ore genesis, as well as of secondary enrichment, appeared in his later publications and profoundly influenced the work of many geologists, including those who studied mining regions under his supervision when he was in charge of the Division of Economic Geology in the U.S. Geological Survey.

BIBLIOGRAPHY

I. Original Works. Emmons’ writings include “Geology of Toyabe Range,” in Geological Exploration of the 40th Parallel, III (Washington, D.C., 1870), 320–348; “Descriptive Geology of the 40th Parallel,” ibid., II (Washington, D.C., 1877), 1–890, written with Arnold Hague; “Abstract of a Report Upon the Geology and Mining Industry of Leadville, Colorado,” in Report of the United States Geological Survey (Washington, D.C., 1882), pp. 203–290; “Statistics and Technology of the Precious Metals,” in Tenth Census Reports, XIII (Washington, D.C, 1885), 1–540, written with G. F. Becker; “Geology and Mining Industry of Leadville, Colorado,” in Monographs of the U.S. Geological Survey, 12 (1886), 1–770; “Structural Relations of Ore Deposits,” in Transactions of the American Institute of Mining Engineers, 16 (1888), 804–839; “Orographic Movements in the Rocky Mountains,” in Bulletin of the Geological Society of America, 1 (1890), 245–286; Geology and Mineral Resources of the Elk Mountains, Colorado, U.S. Geological Survey folio no. 9 (Washington, D.C., 1894); “Geology of the Denver Basin in Colorado,” in Monographs of the U.S. Geological Survey, 27 (1896), 1–556, written with Whitman Cross and G. E. Eldridge; “The Mines of Custer County, Colorado,” in U.S. Geological Survey, Seventeenth Annual Report (Washington, D.C., 1896), pt. 2,411–472; Geology of the Ten-Mile District, Colorado, U.S. Geological Survey folio no. 48 (Washington, D.C., 1898); “Secondary Enrichment of Ore Deposits,” in Transactions of the American Institute of Mining Engineers, 30 (1901), 177–217; “Theories of Ore Deposition, Historically Considered,” in Bulletin of the Geological Society of America, 15 (1904), 1–28; “Development of Modern Theories of Ore Deposition,” in Mining and Scientific Press, 99 (1909), 400–403; “The Downtown District of Leadville, Colorado,” in Bulletin of the United States Geological Survey, no. 320 (1907), 1–75, written with J. D. Irving; and “Cananea Mining District of Sonora, Mexico,” in Economic Geology, 5 (1910), 312–366.

II. Secondary Literature. Biographies of Emmons are George F. Becker, in Transactions of the American Institute of Mining Engineers, 42 (1911), 643–661, with a bibliography of 93 titles; Arnold Hague, in Bulletin of the Geological Society of America, 23 (1912), 12–28, with a bibliography of 94 titles; and in Biographical Memoirs. National Academy of Sciences, 7 (1913), 307–334, with a bibliography of 98 titles.

Kirtley F. Mather