That glaciers should accumulate terminal moraines is axiomatic, but no geologist before 1868 had ventured to suggest where moraines might be located in the United States. In that year Professor Hitchcock delivered a lecture before the Lyceum of Natural History in New York and the Long Island Historical Society in Brooklyn, in which he affirmed that the drift deposits from Prospect Park along the backbone of Long Island for its entire length constituted the terminal moraine of the great continental ice sheet. This declaration inaugurated a new era in the study of the age of ice. The geologists in their several States found the terminal moraines, and the various phenomena began to be classified according to new laws. The search for moraines has resulted in a restatement of the incident of the age of ice; more than a dozen successive terminal moraines have been mapped between New York and Montana, which suggest to us the existence of several glacial periods. In compiling a catalogue of observations of the course of glacial striæ by the United States Geological Survey, it was found that Professor Hitchcock had recorded for New England as many as all other geologists had observed for the whole country.
_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.