in the fourth and fifth columns of the diagram there is a somewhat corresponding division, only under the more scientific name of the Eolithic period, the Lower Paleolithic period, the Upper Paleolithic period, and the Neolithic period. Keane associates the Paleolithic, or rough stone age, with the glacial period in Europe, and the Neolithic, or polished stone age, with the period since the ice ages.32 The Upper and Lower Paleolithic periods are different in that the lower period is characterized by the evolution of the almond-shaped (amygdaloid) implement which is unknown in the Eolithic period) and rare in the Upper Paleolithic period. This is the typical river drift implement. The eolithic implements differ from the lower paleoliths in that they are extremely rough, so primitive indeed that some archeologists have hesitated to recognize them as the work of man. They are natural flakes, chips, or nodules of flint that bear traces of utilization and of having been fitted to the hand.33 Returning to the Lower Paleolithic period of our diagram, we find that there are four well defined epochs based on both stratigraphy and the evolution of the almondshaped implement. These are the Strépyan, Chellean, and the lower and upper Acheulian.34 The fact that archeologists and anthropologists have found it necessary to distinguish between different types of implements shows how there was a gradual evolution of this very low and rudimentary culture to higher and higher stages. Each of these different periods extended over thousands of years. In the Chellean epoch, the almond-shaped im 32 Keane, op. cit., pp. 54-55. 33 See figure 24. 34 See figures 27, 28 and 29. plement is well defined although the scars left by chipping the two faces are still large and somewhat irregular. It is the regularity and the fineness of the chipping which FIGURE 31. Flint Implements of the Mousterian Epoch. distinguishes the Acheulian from the Chellean. Indeed, it is so skilfully done as virtually to eliminate the zigzag nature of the edge formed by the meeting of the two chipped faces.35 The men of the old river drift must have had strong arms and skilful fingers, for it must have 35 MacCurdy, G. G.-"The Caveman as Artist," Century, July, 1912, vol, lxxxiv., p. 440, |