“The State of Massachusetts commissioned him to make a geological survey of her territory in 1830. Three years were spent in the explorations, and the work was of such a high character that other States were induced to follow the example of Massachusetts.... The State of New York sought his advice in the organization of a survey, and followed his suggestions, particularly in the division of the territory into four parts, and appointed him as the geologist of the first district. He entered upon the work, but after a few days of labor he found that he must necessarily be separated from his family, much to his disinclination. He also conceived the idea of urging a more thorough survey of his own State; hence he resigned his commission and returned home. The effort for a resurvey of Massachusetts was successful, and he was recommissioned to do the work. The results appeared in 1841 and 1844.”
Oliver P. Hubbard was assistant to Silliman in 1831–1836, and then up to 1866 taught chemistry, mineralogy, and geology at Dartmouth College. James G. Percival was graduated at Yale in 1815, and in 1835 he and C. U. Shepard of Amherst College were appointed state geologists of Connecticut. Their report was issued in 1842.
James Dwight Dana (1813–1895) was undoubtedly the ablest of all of Silliman’s students. Graduated at Yale in 1833, he spent fifteen months in the United States Navy as instructor in mathematics, cruising off France, Italy, Greece, and Turkey. In 1836 he was assistant to Silliman, and in 1837, at the age of twenty-four years, he published his widely used System of Mineralogy. Two years later Dana joined the Wilkes Exploring Expedition as mineralogist, returning to America in 1842; his geological results of this expedition were published in 1849. In 1863, during the Rebellion, he published his Manual of Geology, and through four editions it remained for forty years the standard text-book for American geologists.
First American Geological Society.—The founding in 1807 of the Geological Society of London, the parent of geological societies, undoubtedly had its stimulating effect on Silliman, and with his marked organizing ability he began to think of forming an American society of the same kind. This he brought about the year following the appearance of the Journal, that is, in 1819. The American Geological Society, begun in 1819 (1, 442, 1819), was terminated in 1830 (17, 202, 1830). The first meeting (September 6, 1819) and all the subsequent ones were held in the cabinet of Yale College. The brief records of the doings of this society are printed in volumes 1, 10, 15, and 18 of the Journal. Silliman was the attraction at the meetings, surrounded by his mineral cabinet, and he gave “the true scientific dress to all the naked mineralogical subjects” discussed.
Wernerian Geology in North America.
The Father of American Geology.—Historical Geology begins in America with William Maclure’s Observations on the Geology of the United States, issued in 1809. This was the first important original work on North American geology, and its colored geological map was the first one of the area east of the Mississippi River. The classification was essentially the Wernerian system. All of the strata of the Coastal Plain, now known to range from the Lower Cretaceous to Recent, were referred to the Alluvial. To the west, over the area of the Piedmont, were his Primitive rocks, while the older Paleozoic formations of the Appalachian ranges were referred to the Transition. West of the folded area, all was Floetz or Secondary, or what we now know as Paleozoic sedimentaries. The Triassic of the Piedmont area and that of Connecticut he called the Old Red Sandstone, and the coal formations of the interior region he said rested upon the Secondary. The second edition of the work in 1817 was much improved, along with the map, which was also printed on a more correct geographic base. (For greater detail, see Merrill, Contributions to the History of American Geology, 1906.)
Even though Maclure’s geologic maps are much generalized, and the scheme of classification adopted a very broad one, they are in the main correct, even if they do emphasize unduly the rather simple geologic structure of North America. This fact is patent all through Maclure’s description. Cleaveland also refers to it in his treatise of 1816, and Silliman in the opening volume of the Journal (1, 7, 1818) says: “The outlines of American geology appear to be particularly grand, simple, and instructive.” Then, all the kinds of rocks were comprehended under four classes, Primitive, Transition, Alluvial, and Volcanic. It is also interesting to note here that in 1822 Maclure had lost faith in the aqueous origin of the igneous rocks and writes of the Wernerian system as “fast going out of fashion” (5, 197, 1822), while Hitchcock said about the same thing in 1825 (9, 146).
The Work of Eaton.—Amos Eaton, after traveling 10,000 miles and completing his Erie Canal Report in 1824, “reviewed the whole line several times,” and published in 1828 in the Journal (14, 145) a paper on Geological Nomenclature, Classes of Rocks, etc. The broader classification is the Wernerian one of Primitive, Transition, and Secondary classes. Under the first two he has fossiliferous early Paleozoic formations, but does not know it, because he pays no attention anywhere to the detail of the entombed fossils, and all of his Secondary is what we now call Paleozoic. The correlations of the latter are faulty throughout.
Then came his paper of 1830, Geological Prodromus (17, 63), in which he says: “I intend to demonstrate ... that all geological strata are arranged in five analogous series; and that each series consists of three formations; viz., the Carboniferous [meaning mud-stones], Quartzose, and Calcareous.” We seem to see here expressed for the first time the idea of “cycles of sedimentation,” but Eaton does not emphasize this idea, and the localities given for each “formation” of “analogous series” demonstrate beyond a doubt that he did not have a sedimentary sequence. The whole is simply a jumble of unrelated formations that happen to agree more or less in their physical characters.
“I intend to demonstrate,” he says further, “that the detritus of New Jersey, embracing the marle, which contains those remarkable fossil relics, is antediluvial, or the genuine Tertiary formation.” This correlation had been clearly shown by Finch in 1824 (7, 31) and yet both are in error in that they do not distinguish the included Cretaceous marls and greensands as something apart from the Tertiary.