300 
:v£R. PEEST^YICH OX flixt-imple:hexts. 
find the white sand d (figs. 1, 2, p. 284), in which the flint-implements are chiefly found, 
in any way disturbed. The depths noted on some of the specimens in de Perthes' 
collection, such as 4, 5, 6, and 7 metres, sufficiently remove them from the probabiliri' 
of ordinary superficial disturbing causes. • 
Rents may have arisen from desiccation of the surface or from earthquake movements. 
In the former case, such gaps would necessarily be filled up from the sides or from the 
surface, and a vertical seam of matter, differing more or less fr’om the beds it cut through, 
would be traceable from the surface down to the flint-implements, but there is not the 
slightest appearance of such a state of things in these pits. The same objection would 
apply to openings produced by earthquake movements, though to a lesser extent, as 
such might have closed up again and not remained open until filled up. Still, with 
gaps in such loose materials, and on the assumption that the flint-implements them- 
selves fell into such gaps, other stones, dirt, and parts of the walls must ineritably have 
also fallen down and shown traces of the presence of materials foreign to the several 
beds ; this is not the case. Also the fine lamination common in the bed of sand (c) 
forms continuous and unbroken lines. Besides, as irreconcileable with any contingency 
which would have led to the introduction of the flint-implements fr’om the ground above, 
the flint-implements are dispersed singly and iiTegularly, are limited to the one lower 
series, and lie apparently flat in the gravel, and not edgeways or downwards. The speci- 
men extracted by myself was certainly, and the one found by Mr. Flower was apparently, 
in that position. In a certain proportion of the specimens from St. Acheul, I have also 
observed that the two sides of the flint-implements present a different appearance, being 
stained and coloured differently ; sometimes one side is fresh and dark, the other white 
and with dendritic markings; others are white on one side and brown on the other; 
others again have a calcareous film on one side only. These appearances may arise from 
the specimens having lain between differently coloured seams of the gravel, or from the 
percolation of water lodging on one surface more than on the other; but in no case 
could it have arisen had they been edgeways or endways in the gravel. In such posi- 
tions one end, portion, or segment might be stained or marked differently to the other 
end or another portion, but the two flat sides could not possibly have been immersed 
each in a different medium, in the way indicated by their present condition. 
The remaining question, whether the fossil bones may have been derived Irom an 
older deposit, presents a contingency requiring especial notice. That sucli a case is 
possible, is evident from the circumstance of fossils and debris of various Tertiary 
strata being found in the gravel. Still there are, I think, valid objections to this sup- 
position. 1. The fragments of bones, although constantly found with their sharp angles 
worn and blunted, never assume a rounded pebble-form, or exhibit an extent ot wear 
materially differing from or exceeding that to which the flint-implements themsehes 
have been subjected ; while, as a general rule, the entire bones and the teeth are either 
not rolled at all, or are so slightly so, as rarely to be in any way injured by attrition. 
If the bones were really derived from an older bed, then consequently they would 
