Daly Reginald Aldworth

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Daly Reginald Aldworth

(b. Napanee, Ontario, Canada, 18 March 1871; d. Cambridge, Massachusetts, 19 September 1957)

geology, geophysics.

Daly’s father Edward, was a tea merchant and farmer; his mother was the former Jane Marie Jeffers. As a boy Daly displayed no interest in geology or in his early schooling. He graduated from Napanee High School in 1887 and received an A.B. degree from Victoria College of the University of Toronto in 1891, remaining there the next year as instructor in mathematics. While there, according to his own notes, his interest in the science to which he devoted his life was stimulated by A. P. Coleman, professor of geology at the University of Toronto.

In 1892 Daly entered Harvard University for graduate studies, earning the M.A. in 1893 and the Ph.D. in 1896. After two years of postdoctoral studies at Heidelberg and Paris, he was an instructor in geology at Harvard from 1898 to 1901. He then accepted the post of geologist with the Canadian International Boundary Commission and from 1901 to 1907 was engaged in arduous fieldwork in the rugged mountainous area of western Alberta and southern British Columbia. For the next five years he was professor of physical geology at the Massachusetts Institute of Technology, and in 1912 he became the Sturgis Hooper professor of geology at Harvard, a post that he held until his retirement in 1942. He became a citizen of the United States in 1920.

Daly married Louise Porter Haskell of Columbia, South Carolina in 1903. Their only child, Reginald, Jr., died in his third year. Mrs. Daly’s death in 1947 was a severe blow, and Daly’s output of scientific papers dwindled thereafter. The robust health that had earlier sustained his strenuous fieldwork deteriorated, and during the last few years of his life he was virtually confined to his home.

Daly was a member or corresponding member of more than a score of scientific organizations and received numerous honorary degrees, awards, and prizes.

A strong advocate of fieldwork, imaginative thinking, and synthesis, Daly practiced what he preached. His earlier fieldwork was chiefly in New England, although he made a trip to Newfoundland and Laboratory in 1900. His six field seasons along the Canadian–American boundary in 1901–1907 were followed by field studies that took him to the scandinavian countries, Hawaii, Samoa, St Helena, Ascension Island, and South Africa. Everywhere he found problems that involved far–reaching geological principles and often led to new concepts. Thus his fieldwork at Mt. Ascutney, Vermont, stimulated the development of his theory of magmatic stoping during the emplacement of intrusive igneous rocks, and later field studies induced detailed examination of theories of magmatic differentiation to explain the great variety of such rocks. Similarly, Daly’s theory of glacial control in the development of coral atolls followed his field studies of Pacific islands. That theory was also involved in his later suggestion that submarine canyons on continental slopes were eroded by turbidity currents. His long–sustained interest in isostasy stemmed from his fieldwork in Labrador, with its elevated postglacial marine shorelines. This in turn led to his geophysical studies, concerned primarily with the strength of the earth’s crust and the structure of the interior of the earth.

His seven books and many of his contributions to technical journals testify to Daly’s ability to correlate countless observations into coherent genetic syntheses. Thus his impact upon geological thinking was worldwide and long–lasting.


I. Original Works. Daly’s writings include “The Geology of the Northeast Coast of Labrador,” in Bulletin of the Museum of Comparative Zoology at Harvard College, 38 (1902), 205–270; “The Geology of Ascutney Mountain, Vermont,” in Bulletin of the United States Geological Survey (1903), 209; “The Mechanics of Igneous Intrusion,” in American Journal of Science, 4th ser., 15 (1903), 260–298, and 16 (1903), 107–126; “The Classification of Igneous Intrusive Bodies,” in Journal of Geology, 13 (1905), 485–508; “The Differentiation of a Secondary Magma Through Gravitative Adjustment,” in Festschrift für Karl Rosenbusch (Stuttgart, 1906), pp. 203–233; “The Nature of Volcanic Action,” in Proceedings of the American Academy of Arts and Sciences, 47 (1911), 47–122; Geology of the North American Cordillera at the Forty–Ninth Parallel, Geological Survey of Canada, memoir no.38 (Ottawa, 1912); Igneous Rocks and Their Origin (New York, 1914); Origin of the Iron Ores at Kiruna, Geology of the Kiruna District, no.5 (Stockholm, 1915); “The Glacial–Control Theory of Coral Reefs,” in Proceedings of the American Academy of Arts and Sciences, 51 (1915), 157–251; “Metamorphism and Its Phases,” in Bulletin of the Geological Society of America, 28 (1917), 375–418; “Genesis of the Alkaline Rocks,” in Journal of Geology, 26 (1918), 97–134; “The Earth’s Crust and Its Stability,” in American Journal of Science, 5th ser., 5 (1923), 349–2371; “The Geology of Ascension Island,” in Proceedings of the American Academy of Arts and Sciences, 60 (1925),1–80; “Carbonate Dikes of the Premier Diamond Mine, Transvaal,” in Journal of Geology, 33 (1925), 659–684; Our Mobile Earth (New York, 1926); “The Geology of Saint Helena,” in Proceedings of the American Academy of Arts and Sciences, 62 (1927), 31–92; “Bushveld Igneous Complex of the Transvaal.” in Bulletin of the Geological Society of America, 39 (1928), 703–768; Igneous Rocks and the Depths of the Earth (New York, 1933); The Changing World of the Ice Age (New Haven, 1934); “Origin of ‘Submarine Canyons,’” in American Journal of Science, 5th ser., 31 (1936), 401–420; Architecture of the Earth (New York, 1938); Strength and Structure of the Earth (New York, 1940); The Floor of the Ocean (Chapel Hill, N. C., 1942); “Meteorites and an Earth Model,” in Bulletin of the Geological Society of America, 54 (1943), 401–455; and “Origin of ‘Land Hemisphere’ and Continents,” in American Journal of Science, 249 (1951), 903–924.

II. Secondary Literature. Biographies of Daly are Francis Birch in Biographical Memories. National Academy of Sciences, 34 (1956), 31–64; and Marland P. Billings, in Proceedings. Geological Society of America, 1958 (1959), 115–122, which includes a bibliography of 134 titles.

Kirtley F. Mather