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268 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 ¥ 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.

The Dartmouth College Museum is filled with specimens accumulated by the energy of Professor Hitchcock. They concern geology, paleontology, petrography, economic botany, and conchology.