968 The American Naturalist. [November, 
As to the artificially chipped flints (see Fig. 3), twelve of 
those obtained by me were patinated with the brown, yellow, 
red and white patina that no art can adequately reproduce, 
for the forged patina is a crust, the real a decomposition into 
the stone. To prove that they, like the fossils, came from the 
gravels, no evidence was wanting save that of a personal dis- 
covery. 
COMPARISON WITH TRENTON SPECIMENS. 
Did the Trenton forms resemble these French objects? 
was the next question. Figure 3 (omitting the so-called Mou- 
sterian flakes specialized on one side, and the thin, knife-like 
flakes and hammer stones from the upper beds) gives the three 
FIG. i 
Typical specimens of flint from the Somme gravels at Abbeville. D’Ault du Mesnil 
collection. (Photographed by the kind permission of M. G. d’Ault du Mesnil.) 
A. Specialized only at the point. Rude at the base. 
B. Specialized all round. Leaf-sha 
C. Unspecialized. Resembling usual Toenton forms. 
* Some “ forging” of specimens has been carried on in the Somme Val- 
ley, as the drawers full of imitations at St. Germain, and the specimens 
shown me in the Du Mesnil collection prove. M. du Mesnil has even detec- 
ted skillful attempts at imitation of white patina at Amiens. He informed 
me that my unpatinated specimens were genuine. But they can be elimi- 
nated from the evidence without depriving it of much force. 
