Professor Henry C. Lewis, of the Pennsylvania Geological Survey, states that “at the localities on the Pennsylvania Railroad, where extensive exposures of these gravels have been made, the deposit is undoubtedly undisturbed. No implement could have come into this gravel except at a time when the river flowed upon it, and when they might have sunk through the loose and shifting material. All the evidence points to the conclusion that at the time of the Trenton gravel flood, Man, in a rude state, with habits similar to those of the river-drift hunter of Europe, and probably under a climate similar to that of more northern regions, lived upon the banks of the ancient Delaware, and lost his stone implements in the shifting sands and gravel of the bed of that stream.”[57] To this Dr. Abbott adds: “At just such a locality as Trenton, where the river widens out, traces of man, had he existed during the accumulation of the gravel, would be most likely to occur. This is true not only because there is here the greatest mass of the gravel, and the best opportunities for examining it in section, but the locality would be one most favourable for the existence of man at the time. The higher ground in the immediate vicinity was sufficiently elevated to be free from the encroachments of the ice and water, and the climate, soil, and fauna are all such as to make it possible for man to exist at this time in this locality.”[58] In 1878 the tusk of a mastodon was found under partially stratified gravel at a depth of fourteen feet; and Dr. Abbott states that, within a few yards of this, palæolithic implements have been gathered, one at the same and three at greater depths. Now that an intelligent interest has been awakened in the subject, numerous labourers are enlisted in its elucidation. To this a coherent unity has been given by the archæologists of the Peabody Museum at Harvard, and the curators of the National Museum at Washington. The results of a systematic inquiry by the latter into the localities and numbers of examples of supposed palæolithic works of art already recovered, have disclosed abundant confirmatory evidence. Special attention was invited to the occurrence of surface-finds, as well as to the depth and the geological indications of age in those recovered from excavations or chance exposures under the surface. Of the superficial examples the proof of the occurrence of stone implements of palæolithic types over widely diffused areas, from New England to Texas, is abundant. Much caution is required in the conclusions derived from such implements found exposed, or in superficial deposits, on a continent where weapons and implements of stone are still in frequent use. But after the elimination of all doubtful examples, abundant evidence remains of the presence of man on the American continent in a Palæolithic as well as an early Neolithic age. An interesting _résumé_ of recent evidence is embodied in the “Results of an Inquiry as to the