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.