536 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
This table is as eloquent as figures alone can be. We are forced to 
the conclusion that the general rule of one-sided marginal chipping, 
beginning at the edge and extending over the back, is the expression 
of a distinct definite purpose. We know the reason for it, namely, 
utility. Natural agencies are not moved by any such definite pur- 
pose. Thus, when we find flint flakes, no matter where, that possess 
a bulb of percussion; when, further, these flakes show series of chip- 
pings all on one side, and when 95 per cent of the specimens are 
chipped according to the rule laid down, we can not then escape the 
conclusion that the pieces in question are artifacts. Among the 
eolithic industries at present known, there are only two where the 
bulb of percussion is at all common. The first is the Cantalian of 
upper Miocene age, the second is at the top of the eolithic series, the 
so-called Mesvinian at the summit of the lower Quaternary. 
Before definitely lopping off the first and third divisions of the 
stone age, it would be well to note their position and relative weight in 
-the chronological scale. A table of classification in harmony with the 
teachings of both Rutot and Penck is reproduced in plate 1. It will 
be seen that the eolithic probably begins with the middle Oligocene, 
reappears in the Miocene and Pliocene, and is carried up through the 
lower Quaternary. The paleolithic, once considered as commensurate 
with the whole of the Quaternary, is now limited to its middle and 
upper horizons. The neolithic is confined to post-Quaternary times. 
The contributions to our knowledge of the paleolithic during the 
decade in question may for convenience be grouped under three 
heads: (1) Those relating to finds in valley deposits; (2) cavern 
explorations, and (3) the discoveries of human skeletal remains. As 
examples of the first group, I have chosen the researches of Commont 
at Saint-Acheul (France) and of Szombathy, Hoernes, and Ober- 
maier at Willendorf (Austria-Hungary). 
VALLEY DEPOSITS. 
The housing and transporting required by modern civilization 
have led to the discovery of the culture levels attained by our 
paleolithic forebears. At Saint-Acheul the deposits of the Somme 
Valley have been exploited since 1771 at least. They yield not only 
material for building purposes, but also sand for foundries and flint 
for road metal. The first discovery of a paleolithic industry at 
Saint-Acheul was made by Doctor Rigollot in 1854, following on and 
inspired by Boucher de Perthes’s discoveries at Abbeville. Then came 
Gaudry, Prestwich, and Evans, all now dead. Explorations at Saint- 
Acheul have been carried on for the past twenty-five years by d’Acy. 
The most active investigator on the ground at present is V. Commont, 
whose systematic work there covers a period of nearly ten years. 
“The writer spent a day at Boncelles but failed to find an eolith. 
