More primitive, and less shapely therefore, than the Mafflian implements, are the forms designated 'Reutelian.' They are referred to the dawn of the Quaternary or Pleistocene period. But with these the initial stage of evolution seems to be reached. Such 'eoliths,' as they have been termed, are only to be distinguished by experts, and even these are by no means agreed in regarding them as products of human industry. If judgment on this vital point be suspended for the moment, it will be seen that Professor Rutot's scheme carries this evidence of human existence far back into the antiquity denoted by the lapse of the Pliocene and Miocene periods of geological chronology. But let it be remarked that when the names Kentian, Cantalian and Fagnian are employed, no claim is made or implied that three distinctive types of implement are distinguished, for in respect of form they are all Reutelian.
Herein the work of M. Commont must be contrasted with that of Professor Rutot. For the gist of M. Commont's researches lies in the demonstration of a succession of types from the more perfect to the less finished, arranged in correspondence with the superimposed strata of a single locality. A vertical succession of implements accompanies a similar sequence of strata.
Professor Rutot examines the Pliocene deposits in England, Miocene in France and Oligocene in Belgium, and finds the same Reutelian type in all. The names Kentian, Cantalian, and Fagnian should therefore be abandoned, for they are only synonyms for Pliocene-Reutelian, etc.
It is hard to gain an idea of the enormous duration of human existence thus suggested. But a diagram (Fig. 24) constructed by Professor Penck[32] is appended with a view to the graphic illustration of this subject. The years that have elapsed since the commencement of the Oligocene period must be numbered by millions. The human type would be shewn thus not merely to have survived the Hipparion, Mastodon and Deinotherium but to have witnessed their evolution and the parental forms whence they arose.
[Illustration: Fig. 24. Chart of the relative duration of Miocene, Pliocene and Pleistocene time: (From Penck.)
1. Line of oscillation of level of lowest snow-line. (Central Europe.)