Ebenezer Emmons (1799-1863)
Rensselaer Class of 1826

Compiled by D. J. Cherniak
Associate Research Professor
Department of Earth & Environmental Sciences
Rensselaer Polytechnic Institute
Troy, NY 12180

Dr. Ebenezer Emmons Sr., Rensselaer Alumnus and American science pioneer.
In his classical paper "Ebenezer Emmons and the Foundation of American Geology", published in 1969, Cecil J. Scheer of the University of New Hampshire writes, "If we were to limit our study to the selection of any single individual as principally responsible for [this] transformation in American geology it would have to be Professor Ebenezer Emmons."Emmons' work served as a model and a standard for the geologic-stratigraphic surveys for the rest of the United States. Following from work in New York State, where equivalence with European rock formations had been sought, the developing classical geology in the United States had as its principal aim the determination of stratigraphic units and positions equivalent to those investigated in New York State. As New York geologists (chief among them Emmons) established a localized nomenclature, distinguishing structures by rock type, fossils present, and order of rock layers, the same detailed characterization of the geology was developed for the rest of the country.

Ebenezer Emmons Sr. was born in 1799. He graduated in 1818 from Williams College, where he studied medicine. Pioneer geologist Chester Dewey was also one of his instructors. Following an internship at the Berkshire Medical School, Emmons practiced medicine in Chester, Massachusetts. He still longed to pursue his interest in geology, so decided to attend the Rensselaer School (now RPI). There, he was inspired by the eminent professor Amos Eaton, and graduated from Rensselaer in its first class in 1826.

Cover page from Emmons Manual of Mineralogy and Geology
In this year of his graduation, Emmons authored the Manual of Mineralogy and Geology, a textbook that was the second treatise of its kind written by an American for American students of geology. It went through several editions, indicating its popularity as a text. During his career, Emmons wrote several other classic texts, reflecting his expertise in geology and other aspects of natural history. Among these were the Report of the Second Geological District of New York (1842), Natural History of New York (1848), American Geology, Containing a Statement of Principles of the Science with Full Illustrations of the Characteristic American Fossils (1854), A Treatise Upon American Geology (1854), The Swampland of North Carolina (1860), and Manual of Geology (1860). Also notable was his beautifully illustrated multi-volume set, the Agriculture of New York State, published between 1846 and 1854.

Cover page from Emmons' American Geology.
In 1828, Emmons returned to Williams as a lecturer in chemistry. He returned to Rensselaer in 1830, where he again worked with Amos Eaton, serving as a Junior Professor of Mineralogy and Geology. He remained at Rensselaer until 1839. In those years, Emmons was also active in scientific organizations. The formative meeting of the American Association of Geologists took place at Emmons' home in Albany in 1838. This organization was the predecessor of the American Association for the Advancement of Science.

During this period, Emmons also began work for the New York State Geological Survey. Emmons became the State (Chief) Geologist for the northern New York State Geological District in 1836. In this capacity, he named the Adirondacks (1838) and Taconic Mountains (1844). He also organized and led the first recorded ascent of Mt. Marcy (in 1837), naming the peak for New York State Governor William Learned Marcy. Emmons' interest in and writings on the Adirondacks also led to the increased acquaintance of the public with these regions. As a member of the New York State Natural History Survey, he advocated mining and other uses of the area's abundant resources. At the same time, he promoted the idea of the Adirondacks as a place of natural beauty in which to retreat for recreation and rejuvenation as antidote to an increasingly industrialized and urbanized nation.

Emmons house, on the corner of Hudson Ave. and High St. in Albany, hosted the formative meeting of the American Association of Geologists on November 20, 1838. The Association would later evolve into the modern-day American Association for the Advancement of Science (AAAS). The house was demolished in the late 1960's to make room for the Empire State Plaza.
While working with the New York State Geological Survey, Emmons had a well publicized disagreement with James Hall and others over Emmons' Taconic System classification. He had proposed the Taconic System to describe the formation of the Taconic Mountains and rocks of easternmost New York and western Massachusetts. Emmons had given an older Cambrian age to these rocks while Hall argued that they were younger, of Ordovician age. The Taconic Orogeny (mountain-building event) occurred when a volcanic island arc collided with a proto-North American continent; these two land masses came together and closed a former ocean. This event affected a region from Newfoundland to Alabama, now the Appalachians. Rocks which had originally been deposited in a deep-water area were stacked together by these plate collisions and formed the Taconic Mountain range. This overthrust, with older rocks sitting atop younger rocks, is visible in Troy (and runs through the RPI campus). Fossils later found in parts of these rocks helped decipher the relative ages of the rocks and eventually led to proof that Emmons was indeed correct. The line of closing of that former ocean, marked by ultramafic rocks in the Appalachians, was once called Logan's Line (to honor William Edmond Logan, 1798-1875), and now named Emmons' Line (to honor Ebenezer Emmons).

Unfortunately, Emmons was not vindicated immediately. At the time, his dispute with Hall, which made its way to the courts of New York State, led to Emmons being prohibited from practicing geology in New York. He sued Hall for slander and libel but lost the case. He went on to North Carolina, and became its first State Geologist. While there, he made the first discovery of fossil teeth of Deinosuchus (a giant ancient crocodile, which preyed on carnivorous dinosaurs).

Emmons died in 1863. Ironically, his body was returned to the Troy area and he was buried in Albany Rural Cemetery, just a few feet from what would later be the final resting place of James Hall.

John Rodgers (Yale University) writes:

Emmons was a student of Amos Eaton (1776-1842), and Chester Dewey (1784-1867) at Williams College in Williamstown, Mass., and later he taught there and at Eaton's Rensselaer School or Institute in Troy, N.Y. (now RPI). When the State of New York, spurred by Edward Hitchcock's big report of Massachusetts (1833), decided to support a geological survey, not one but four geologists were appointed for the much larger state; they were Lardner Vanuxem (1792-1848), Ebenezer Emmons (1799-1863), Timothy Conrad (1803-1877), and William M. Mather (1804-1859). Eaton was consulted about the appointments, and he recommended Emmons and Mather, and also James Hall (1811-1898), another of his pupils and colleagues at Rensselaer; when after the first field season Conrad was appointed state paleontologist, Hall became the fourth geologist. Emmons was assigned the northern district of the state, including the largest part of the wild and then almost unknown Adirondack Mountains - indeed Emmons gave them that name and some of the fringe of settled land around them.

Emmons did a thorough piece of work, both on the "Primary" rocks of the mountains and on the almost flat-lying "Transition" strata that lie unconformably above and dip gently away in all directions. With his colleagues, especially Vanuxem and Hall, he established the stratigraphic sequence in these "Transition" strata, which quickly became the standard column for the pre-Carboniferous Paleozoic rocks of North America, definitively replacing the crude Wernerian subdivisions that Eaton had proposed in his Erie Canal traverse (1824). At Emmons' suggestion, the four geologists named this sequence the "New-York System" or the "New-York Transition System", and truly it is a better stratigraphic standard than the Cambrian to Devonian systems then being erected in the highly deformed rocks of Britain. Emmons was largely responsible for establishing the units in the lower part of the sequence, the Champlain division (now the Upper Cambrian and Ordovician).

Like his mentor Eaton, Emmons must have driven many times (by horse and buggy) from Williamstown to Troy and Albany, and he was evidently deeply impressed by the complicated rocks he saw along the route. They were in strong contrast to the nearly horizontal strata of the New York System, but not as massive and lacking in stratification as the "Primary" rocks. He tells us (1846, p.208) that at first he taught his students that these rocks were simply (greatly disturbed) "extensions eastward of the lower New York rocks"; i.e., of "Transition" rocks, as Eaton had thought, but, as his knowledge of the flat-lying "Transition" strata in northern New York grew, he abandoned this doctrine and concluded that they formed an independent system intermediate in age between the New York System and the "Primary", and he called in the Taconic System for the Taconic Range of mountains along the border between Massachusetts and New York, just west of Williamstown and southward as far as the northwestern corner of Connecticut. 

 Apparently, Emmons first told his colleagues about his new system in late 1839 or early 1840, probably when the New York State Survey geologists met to compare their results, and possibly also at the meeting of the Association of American Geologists in Philadelphia in April 1840.


J. Rodgers (1989) The Taconic Controversies. In: The 28th International Geological Congress Field Trip Guidebook T169, Boston to Buffalo in the Footsteps of Amos Eaton and Edward Hitchcock. Eds.: W.M. Jordan, G.M. Friedman, T.X. Grasso, J. Rodgers, E.S. Belt, M.E. Johnston, and R.S. Naylor

Many thanks to G.M. Friedman, Professor Emeritus at Renssealer for his expertise and materials on E. Emmons.

©2005 RPI E&ES

Formatted for the web by J.D. Price


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