attempts seem to have ended in failure. This subject was discussed in my vice-presidential address[1] before section H of the AmericanAssociation for the Advancement of Science at the New York meeting in 1906. The recent discoveries of eoliths on the plateau of Hautes-Fagnes and at Boncelles, near Liège, by de Munck and Rutot, have an important bearing on this whole subject. At Boncelles eoliths are said to be found in undisturbed middle Oligocene deposits, which is the lowest horizon yet recorded for them.
The fact that the Tasmanians when they became extinct in 1876 were still in a culture stage corresponding to the eolithic has done much to strengthen the thesis of that school. In this connection should be mentioned the discovery by Franz de Zeltner in Haute Senegal of a quite recent industry with eolithic facies. Rutot also finds in Belgium that a neolithic epoch, to which he has given the name "Flénusian," is characterized by a similar industry.
But eoliths were introduced here only to be retired from the stage in order that more space might be given to the doings of the paleolithic school. I can not dismiss them, however, without first referring to Verworn's[2] rule of the one-sided marginal working of a flake or chip. No single character is a sufficient basis for declaring that a given stone object is or is not an artifact. Each specimen should be subjected to a systematic diagnosis, as is a case of fever, for example, by a physician, says Verworn. In observing a number of paleolithic or neolithic scrapers that are made from flakes which are retouched on one side only, one finds that the direction from which the retouching took place is almost always oriented in the same manner with respect to the sides of the flake. If one calls the under or bulb side of the flake the front and the outer side the back, one sees that the blows or the pressure which produced the marginal working was executed almost always from the front toward the back, that the tiny scars left by the chipping begin at the margin and extend over the back. The chipping is therefore visible only from the back; only in rare cases does one find the opposite orientation of the chipping.
What is the meaning of this? There is too much method in it to be the result of chance. There is even more than mere method. By following the rule as expressed in figure 1a–c, we arrive at a tool that is utilizable. The edge produced by the chipping is straight, as seen in figure 1 c. On the other hand, if the opposite method of chipping is followed we arrive at a meandering irregular edge-line that is good for nothing from a practical standpoint (fig. 2 c). In rare instances the back of the flake may be more regular than the front.
