406 
THE GEOLOGIST. 
Average 
thickness. 
pliimi and of species of horse, ox, and deer, generally 
near the base. Tliis bed is further remarkable for con- 
taining the ^vorkcd flints ("iiachcs"of M. de Pertlies, 
and "laugues dcs chat" of the workmen) 6 to 12 feet. 
resting on 
Uneven surface of Chalk strata. 
In the stratum 2b tlie flint implements arc found in considerable numbers. 
Mr. Prcstwich tells us in his paper read before the Royal Society, that on his 
first visit he obtained several specimens from the workmen. The late Dr. 
RigoUet mentions the occurrence also here in the gravel of round pieces of 
hard chalk, pierced witli holes, which he considers were used as beads. Such 
were also found by Mr. Prestwich on his visit, and recognized as small fossil 
sponges {Cosciiiopora rjlohularh, D'Orb), very common in the Chalk. He ex- 
presses some doubt about their artificial dressing, although he admits " some 
specimens do certainly appear as though the hole had been enlarged and com- 
pleted." We figure a specimen. 
Supposed Fossil Bea<l. 
These gravel-beds at St. Acheul cap a low chalk hill a mile south-east of the 
city of Amiens, and are about a hundred feet above the valley of the Somme, 
and are not commanded by any higher ground. 
Pig. 2 is also from the gravel of Amiens, and is a very good example of the 
large pear-shaped implements. The specimen No. 2 is a type of another and 
flatter kind, and was probably used as a javelin, or spear-head, while the largest 
pear-shaped specimens like fig. 1 were prol^ably used for digging roots, as the 
upper extremity is unworked, and left bulbous in shape, as if for fitting the palm 
of tile hand wlicn in use. It seems there are two sorts of pear-shaped flints. 
Flint Implement (c) lashed to a stout pole («) by cord (</), as a speai'-liead ; i, notch at end of 
pole for end of instiniment. 
and that some were used like fig. 1 as javelin, or spear-heads. Sir Charles 
Lyell has in his collection one of these worked flints thus lashed on to a stout 
pole, in illustration of their probable use as javelin-heads, of which we give a 
representation below. 
In the gravel deposit on which the town of Abbeville stands, a number of 
flint unplemeuts have been found, together with teeth of Elephas jirimigenius 
and, at places, fragments of fresh-water shells. The section, however, which 
Mr. Prestwich considers of great interest is that at Menchecourt, a subiu-b to 
