Eskers are another interesting class of phenomena, and were first described as horsebacks in Maine, about seventy of them having been described in the report of 1861 and 1862. It was not till after the description of the Swedish Ösar that the nature of these lines or ridges was understood; and now they were found in every prominent valley in New England, as attendant upon the recession of the ice sheet. Professor Hitchcock gave the correct name of these ridges in his Elementary Geology, 1860; while for many years subsequently they were erroneously called kames, even in the geology of New Hampshire.
Professor Hitchcock gave the name of Champlain to the fossiliferous clays associated with the till of the Atlantic coast. The term has come into general use as connected with the melting of the ice in the latter part of the period. Because of the presence of boreal species, and of analogies with similar deposits in Europe, Professor Hitchcock has asked the question whether there may not have been a Champlain glacial epoch posterior to those named farther in the interior of the country, the Kansan, Iowan, and Illinoisian epochs.
Those who explore the geology of northern New England have to deal with crystalline rocks of various ages, and the opinions of our best geologists have not been in agreement respecting them. Professor Hitchcock was the first to make a geological map of New Hampshire, and he also demonstrated the anticlinal nature of the Green Mountains of Vermont. His teachers had inculcated the view that these eminences belonged to a synclinal disposition, coupling this with theoretical assertions as to their age and metamorphism. Finding their main principle to be erroneous, he naturally disparaged their theories, though more recent studies are eliminating many of the schists from the Archæan. All the later explorers in the field—Canadians and members of the Geological Survey—accept a pre-Cambrian anticlinal in the heart of the Green Mountains.
The distribution of the New Hampshire formations was made out for the most part before any assistance was derived from the labors of Dr. G. W. Hawes and other petrographers. Twenty years ago, at the date of the final publication of the New Hampshire maps, the doctrine of an igneous origin of the crystalline schist had hardly been hinted at. What seems elemental to the modern petrographer who has acquired his technical education since 1890 was unknown then, and the classification given in the report may not agree with that now taught. In the midst of the diverse views entertained, Professor Hitchcock classified the rocks of northern New England according to this principle: rocks that are identical in petrographical composition are assumed to have had the same origin, and to be synchronous. Professor Hitchcock was almost the first of American geologists to employ the petrographer as a help to the understanding of the crystallines—as was evident by the very valuable contributions to knowledge in Part IV of the New Hampshire Report as prepared by Dr. Hawes.
A vexing question concerning what are now called Cambrian terranes divided geologists for a quarter of a century after 1857, and had to be considered in preparing the geology of Vermont in 1861. This was the Taconic controversy. Trilobites had been discovered in Vermont, which were misunderstood by most of the American geologists following Hall, Logan, Dana, and others. In giving the species the technical name first of Barrandesi and then Olenellus, Prof. James Hall asserted its derivation from the Hudson River group—relying upon the stratigraphical determinations of Sir W. E. Logan. As soon as Barrandes's attention was called to these trilobites and the attendant publication, he wrote his famous letter to Logan in 1860, declaring that there must be a mistake somewhere. That error was discovered in time to be eliminated from the Vermont report of the following year. Professor Hitchcock had charge of the field work in this Cambrian district, and his views of the arrangement of the formations are in agreement with those of the latest workers in the field. He applied the term of Georgia to one division of the terrane in 1860; and the designation has been generally adopted since that time. Jules Marcou claimed priority in the suggestion of the application of the term, but upon the publication of Professor Hitchcock's statement on the subject the credit of priority was awarded to him by Director Walcott, of the United States Geological Survey.
Between 1860 and 1870 Professor Hitchcock was occupied largely as a mining geologist in the estimation of mineral deposits for mining companies, with his office in New York. In the prosecution of this business he traveled in Nova Scotia, New Brunswick, Quebec, Maine, New Hampshire, Vermont, New York, New Jersey, Pennsylvania, Maryland, Virginia, Ohio, Kentucky, and Alabama. Subsequently, the study of the phosphate beds led him to the island of Redonda in the West Indies. He further visited the phosphate beds of South Carolina and Florida, the gold fields of eastern Oregon, the Chalcedony Park of Arizona, the Grand Cañon of the Colorado, and the Yosemite and Yellowstone Parks. Studies made in the Hawaiian Islands and their volcanoes in 1883 and 1886 resulted in the contribution of important observations respecting those regions. At the present writing Professor Hitchcock is spending a year of further observations in those islands.
Mr. Hitchcock was appointed, in 1858, lecturer in zoölogy and curator of the cabinet in Amherst College; an office which he filled for seven years, retiring after the death of his father. In 1866 he was elected professor of geology in Lafayette College, where he gave short courses of instruction to five successive classes. In 1868 he was called to the chair of geology in Dartmouth College, a position which he still occupies, receiving a year's leave of absence for 1898-'99 in consideration of thirty years of service. He taught geology and zoölogy as a provisional professor at Williams College in 1881, and in the following year in the Virginia College of Agriculture and the Mechanic Arts, Blacksbury. He received the degree of M. A. in course at Amherst in 1859, the honorary degree of Ph. D. from Lafayette College in 1870, and that of LL. D. from Amherst College in 1896.
Professor Hitchcock has been connected with the American Association for the Advancement of Science since 1856, and a nearly constant attendant upon its meetings and participant in the proceedings. He is a member of local scientific societies in Portland, Me., Boston, Mass., New York, Philadelphia, and St. Louis, and also of the Imperial Geological Institute of Vienna. He was one of the most prominent movers in the inception and early history of the Geological Society of America, and had much to do with the organization of the International Congress of Geologists, and with the preparation of special reports for the several meetings between 1876 and 1890. The handsome geological map of small scale compiled for the United States was prepared by him and published in the Transactions of the American Institute of Mining Engineers (1887), to illustrate the nomenclature and color scheme of the International Congress.
Professor Hitchcock is best known to many by his geological maps. The first efforts at mapping the geology of the United States were made independently by Edward Hitchcock and Jules Marcou in 1883—the work of Mr. Marcou extending only to the plains. Prof. H. D. Rogers, five or six years later, prepared a map for Johnston's Physical Atlas. In 1872 Prof. C. H. Hitchcock and Prof. W. P. Blake compiled a map for the ninth census of the United States, and for R. W. Raymond's report upon the mineral resources of the country. The success of his small scale map led Professor Hitchcock to undertake the preparation of a map on a scale of twenty-five miles to the inch for the whole country. For this he consulted every work that had been printed upon the geology of the United States, and obtained the privilege of using many unpublished data collected by geologists of States and Territories in which the work had never been carried to actual completion. The map prepared by the General Land Office was used as the basis for the geological coloration, and the work appeared in 1881, of a size adapted to use in the classroom. Its compiler has never seen any criticism of its accuracy. The edition prepared for the Mining Institute embodies all the information acquired for the large map, with such additional facts as had been learned since that map was published. Prof. Hitchcock's services were called into requisition in the compilation of a similar map for the United States Geological Survey, which was published in its annual report for 1886, under the editorship of W. J. McGee; in fact, the two maps were printed from the same plates, but Dr. Hitchcock's contained certain features not found in the other one—the result of different interpretations—and was more complete. In the Government edition a system of coloration devised by Major J. W. Powell, which was afterward abandoned, was employed.
Professor Hitchcock contributed extensively to the collection of State geological maps in the Centennial Exhibition of 1876, when large scale sheets of New England, and a large copy of the Hitchcock and Blake map of 1872, were exhibited. A medal was awarded for a sheet of thirteen sections illustrating the stratigraphy of Vermont and New Hampshire. The beginning of the measurement of sections was made for the Vermont Geological Report under the direction of Dr. Edward Hitchcock in 1861. Twelve lines of exploration across the entire State were determined upon, and specimens were collected to illustrate all the varieties of rock seen upon each. The specimens were arranged in the State Museum at Montpelier in geographical order. A similar plan of collection and arrangement was projected for the New Hampshire survey, but it was made to extend across the two States, from Maine to New York. Besides the two State reports, later publications were issued, descriptive of explorations and collections for the Bulletin of the American Museum of Natural History in New York, and the New Hampshire Agricultural Report for 1883. The work did not cease with these publications, for after the transfer of the collection of sections from the New Hampshire College of Agriculture and the Mechanic Arts to Dartmouth College in 1894, additional explorations were made; the number of sections was increased to eighteen; improved drawings of the profiles, colored geologically, were prepared for the cases in the new Butterfield Museum; and the explanation of the details was further facilitated by the construction of a large relief map on the scale of one mile to the inch horizontally, twice as much vertically, and having colors corresponding to those on the profiles between the shelves. About five thousand specimens have been gathered to illustrate the profiles.