298 
ME. PEESTWICM OX FLIXT-DIPLEMEXTS. 
or less, on their chipped or made surfaces, by a film of deposited carbonate of lime (fig. 8); 
some also are marked with superfcial dendritic impressions (fig. 9), — both features 
only to be produced by considerable time, and both common on the flints composing the 
mass of the gravel itself. The preceding figures represent portions (^), twice enlarged, 
of two specimens from St. Acheul on which these characters are exhibited*. 
That we may often pass a considerable time in examining a section of drift gravel 
known to contain mammalian bones, and yet not succeed in discovering any, must have 
been experienced by all who have worked at beds of this age. In such cases the specimens 
are necessarily obtained from the workmen, whose opportunities are constant. I have 
been, time after time, to the well-known pits at Grays Thurrock, which have supplied so 
rich a series of mammahan remains to our museums, and never found a single specimen 
by my own search. At Ilford and Erith I have, on the contrary, readily procured an 
abundance of small specimens with my own hands. Again, the large gravel pit adjoin- 
ing the Croydon Station, was extensively worked for several years before the fragment 
of a bone was found, and then the men found only a few rare pieces of the tooth and tusk 
of the Elephant. When, therefore, the remains are not abundant, the evidence of their 
really occurring in the position assigned to them must depend, in great measiu'e. upon 
the honesty and veracity of the men, and on the concordance and condition of the fossils. 
I have rarely, on such occasions, had cause to doubt the former, nor, after a little expe- 
rience, have I had much difficulty in deciding with regard to the latter. The workmen 
with whom I came into contact in France seemed to me as generally equally deserving 
of confidence. Their testimony was given freely, and was concurrent at each locality, 
and equally so in comparing the different localities between which there was little or no 
communication. Now all the workmen to whom I spoke, both at Abbe^■ille and Amiens, 
were unanimous in assuring me that the flint-implements were found in the midisturbed 
gravel indiscriminately with the fossil bones. Not only did the workmen all agree on this 
point, but the foremen and proprietors of the pits bore testimony to the same fact, — a 
fact which to a certain extent I can now corroborate from my oun experiencef. 
3. Finally, we have to consider whether it is possible for the flint-implements to have 
been introduced into their present position within some comparatively recent period, or 
whether they are contemporaneous with the accumulation of the gravel ; and fiu'ther, 
whether the remains of the large extinct mammals could have been derived from some 
older beds, and therefore be of anterior date to the flint-implenients. 
These implements might have got imbedded in the gravel, — 1st, by artificial excava- 
tions ; 2ndly, by rents in the ground. To anybody accustomed to the examination of 
* Many of these coiisideratious will he foimcl alluded to by M. Bouchek de Pektues, as well as by 
Dr. Eigollot, Dr. L. Doucuet of Amiens aptly observes that tliese incrustations “ sout pour nous ce que 
la patine est pour la medaille la preuve ou le signe impossible k nier de leur antique origine ” (Aiitiq. 
Celt, et Anted, vol. ii. p. 431). 
t That we have to regret attempts at, as well as succcssfid instances of, deception, must be admitted ; 
but that such are the exception to the general rule I am, from long experience, fully satisfied. 
