Emmons, Ebenezer

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Emmons, Ebenezer

(b. Middlefield, Massachusetts, 16 May 1799; d. Brunswick County, North Carolina, 1 October 1863)


Ebenezer Emmons was the focus of the great Taconic controversy, the gravest dispute ever to divide American geology. A principal figure in the first geological survey of New York between 1837 and 1843, he played a leading role in the establishment of a geological column for America and a stratigraphy independent of the Anglo-Continental model. Before the New York survey, correlation with the succession of English strata was the principal objective of American geologists from Maclure and Eaton through Edward Hitchcock and David Dale Owen. By 1842 the Transition strata of New York between the Carboniferous of Pennsylvania and the Primary had been separated into the Catskill, Erie, Helderberg, Ontario, and Champlain groups of a New-York system and a separate Taconic system. The Potsdam sandstone, the Chazy limestone, the black marble of Isle La Motte, and the Lorraine shales, as well as the major group names and the two system designations (New-York and Taconic) were bestowed by Emmons. The strata were characterized both paleontologically and lithologically, and type sections were described by Emmons and his colleagues. The system of nomenclature by geographic reference, adopted for the first time in North America, was specifically the work of Emmons. He also named the Adirondack Mountains,1 and it was at a meeting of the New York Board of Geologists at Emmons’ home in Albany in 1838 that the Association of American Geologists, which developed into the American Association for the Advancement of Science, was planned.

Emmons studied at Williams College and later the Berkshire Medical School, in the midst of the Taconic country. At Williams he was protégé and assistant of Chester Dewey, with whom he began his geological surveys. He joined Dewey in 1828 as instructor and later succeeded him as professor of natural history. In 1826 he was studying geology and assisting Amos Eaton at the newly organized Rensselaer School (now Rensselaer Polytechnic Institute) as well as lecturing in chemistry at the Albany Medical College. Emmons achieved a certain financial independence through the practice of medicine, chiefly obstetrics, which he continued throughout his life.

James Hall was a student at Rensselaer from 1830, the year in which Emmons became junior professor, to 1832. Emmons chose Hall as his assistant in the first field season of his survey of the second New York district. W. W. Mather, Lardner Vanuxem, and T. A. Conrad were initially responsible for the first, third, and fourth of the four districts into which the state had been divided. Hall later succeeded Conrad. Lewis C. Beck was attached to the survey as mineralogist.

Emmons began by tracing an orderly succession of scarcely disturbed fossiliferous strata, beginning with the Potsdam sandstone dipping gently away from the crystalline rocks of the Adirondack outlier. Across the Hudson and Champlain valleys to the east, he found the abrupt front of the Taconic Range, consisting of broken slates with intercalated carbonates, generally dipping steeply toward the crystalline rocks of the New England mountains. In spite of the reverse dip, Emmons had always considered these rocks to be older than the less disturbed shales and carbonates of the Hudson and Champlain valleys2 and now proposed that they constituted a vast new sedimentary series between the Potsdam and the primary, the true primordial system and the base of the sedimentary column. Vanuxem and Conrad, and apparently even Hall at first, agreed. Mather disagreed, as did William and Henry Barton Rogers, whose observations of the merging of the flat rocks of the Allegheny Plateau into the folded strata of the valley and ridge province persuaded Mather that the Taconic strata are an overfolded extension of the Champlain group.

As the original survey was completed, Hall and Emmons were in competition for continuing geological positions with the state, Hall maneuvering to obtain the post of state paleontologist. Although aspiring to the title of state geologist, Emmons was diverted into the position of state agriculturalist.

His Taconic system came under direct attack from the Rogers brothers, who maintained that the entire folded Appalachian chain contained neither faults nor unconformities. In 1844 and again in 1846, in Agriculture of New York, Emmons published a vigorous exposition of the Taconic system, by then supported by paleontological evidence.

James T. Foster, a New York schoolteacher, relying on Emmons’ expertise, prepared a geological map that he succeeded in selling to the New York Legislature in 1850 for use in the schools of the state. Louis Agassiz and Hall (who hurriedly prepared his own rival map) induced the state to cancel the order— Hall going so far, according to his assistant and, later, successor, J. M. Clarke, as to dump Foster’s maps into the Hudson River. Thereupon, Foster sued Agassiz and Hall for libel. The case against Agassiz was heard first, with Emmons the sole witness to the scientific reputability of Foster’s chart. Joseph Henry, James Dwight Dana (who later wrote fifteen papers disproving the Taconic system), J. D. Whitney, the Rogers brothers, Eben Horsford, Mather, Hitchcock, and even Sir Charles Lyell volunteered their testimony in Agassiz’s behalf. The case, which ended in dismissal, amounted to the excommunication of Emmons from the ranks of American science. The following year he accepted the post of state geologist for North Carolina and moved south, there to be caught by the Civil War. He continued to assemble evidence of the wide extension of his pre-Potsdam system, and before his death in 1863 he had the satisfaction of seeing his claim to be discoverer of the “true primordial fauna” and the base of the sedimentary column supported by the contentious Jules Marcou; Joachim Barrande, by then the acknowledged authority on the Lower Paleozoic; the Canadian geologists William Logan and Elkanah Billings; and T. S. Hunt.

A man of stern appearance and strict religious observance, Emmons was nevertheless a popular teacher and greatly in demand as an obstetrician. His controversial views made him an underground favorite among students and younger faculty in the strongholds of his opponents. Successive editions of his textbooks attest to his extended influence. Perhaps more significantly, the Manual of Geology by Dana, his most uncompromising foe,3 closely follows the organization and basic pedagogy of Emmons’ Manual of Geology more than any of the available English examples.

The Taconic controversy, continuing in some aspects to the present day, came to overshadow Emmons’ major contribution to world geology, which was the extension in New York of the method begun by William Smith, Georges Cuvier, and Alexandre Brongniart. It was the New York survey, but especially the New-York system classification and Emmons’ nomenclature, that set the model in America, as Sedgwick and Murchison were setting it in England, for the subsequent development of stratigraphy and the geological time scale in the next century.


1. Wherever possible Emmons took his designations from the names for the original Indian inhabitants. The precedent may have been Murchison and Sedgwick’s Silurian system, first used in 1835, when the New York survey was beginning.

2. He had convinced Hitchcock of this in 1833, but by 1842 Hitchcock had decided that the Taconic rocks were simply metamorphosed Champlain strata (E. Hitchcock, Geology of Massachusetts [Amherst, 1833], p. 300; W. W. Mather, “Geology of the First District,” in Geology, pt. 4 of the Natural History of New York [Albany, 1843]).

3. In 1888, when the evidence of extensive Lower Cambrian fossiliferous strata was incontrovertible, the American Committee of the International Geological Congress recommended the denomination “Taconic system” for the first group of strata above the Archean. The aged and mellowed Hall agreed, but Dana and C. D. Walcott led a successful fight to reject the recommendation.


I. Original Works. Emmons’ most significant publication was the now almost unobtainable final report, “Geology of the Second District,” in Geology, pt. 4 of the Natural History of New York (Albany, 1842). Agriculture of New York, pt. 5 of Natural History of New York (Albany, 1846), contains his geology of New York, the only summary publication of the results of the New York survey. It is profusely illustrated with exceptional lithographs by his son, Ebenezer Jr., and engraved sections, some hand-colored. The text speaks of a map but, according to Marcou, although the map was printed, Hall succeeded in suppressing it. Emmons’ several textbooks made free and presumably profitable use of the fossil illustrations prepared under the direction of the New York Board of Geologists, thereby infuriating Hall.

Emmons’ Manual of Mineralogy and Geology (Albany, 1826; 2nd ed., 1832) should be compared with his last textbook, Manual of Geology (Philadelphia, 1860), to illustrate his lack of concern with theory and a characteristic pragmatic concentration on historical geology. For a complete bibliography, consult John M. Nickles, “Geologic Literature on North America 1785–1918,” U.S. Geological Survey Bulletin no. 746 (1922), 345–346.

II. Secondary Literature. A major source of information about Emmons is J. M. Clarke, James Hall of Albany (Albany, 1923), by Hall’s assistant and successor as New York State paleontologist; see pp. 30, 40, 42, 53, 57, 99, 206. The Taconic controversy is extensively treated in G. P. Merrill, The First One Hundred Years of American Geology (New Haven, 1924), pp. 594–614; a biographical essay by Jules Marcou, American Geologist, 7 (1891), 1–23, is somewhat overblown; the article by G. P. Merrill in the Dictionary of American Biography, III, 149, is unduly deflating. Emmons’ own records apparently were lost in the disorders attendant on his wartime death. Any official records of the Foster v. Agassiz case, beyond the bare fact of its dismissal, were lost in a fire. See C. J. Schneer, “Ebenezer Emmons and the Foundations of American Geology,” in Isis, 60 pt. 4 (1970), 439–450.

Cecil J. Schneer