Occurrence of Flint-implements in Gi'avel-beds. 295 



and barrows. There are specimens, however, of true implements 

 ("haehes")in M. de Perthes' collection from Menchecourt ; one 

 noticed by the author was from a depth of 5, and another of 7 

 metres. This would take them out from bed No. 1, but would 

 leave it uncertain whether they came from No. 2 or No. 3. From 

 their general appearance, and traces of the matrix, the author would 

 be disposed to place them in bed No. 2, but M. de Perthes believes 

 them to be from No. 3 ; if so, it must have been in some of the sub- 

 ordinate clay seams occasionally intercalated in the white sand. 



Besides the concurrent testimony of all the workmen at the dif- 

 ferent pits, which the author after careful examination saw no 

 reason to doubt, the flint-implements ("baches") bear upon them- 

 selves internal evidence of the truth of M. de Perthes' opinion. It 

 is a peculiarity of fractured chalk flints to become deeply and per- 

 manently stained and coloured, or to be left unchanged, according to 

 the nature of the matrix in which they are imbedded. In most clay 

 beds they become outside of a bright opaque white or porcelainic ; 

 in white calcareous or siliceous sand their fractured black surfaces 

 remain almost unchanged ; whilst in beds of ochreous and ferru- 

 ginous sands, the flints are stained of the light yellow and deep brown 

 colours so well exhibited in the common ochreous gravel of the 

 neighbourhood of London. This change is the work of very long 

 time, and of moisture before the opening out of the beds. Now in 

 lookmg over the large series of flint-implements in M. de Perthes' col- 

 lection, it cannot fail to strike the most casual observer that those from 

 Menchecourt are almost always white and bright, whilst those from 

 Moulin Quignon have a dull yellow and brown surface ; and it may be 

 noticed that whenever (as is often the case) any of the matrix adheres 

 to the flint, it is invariably of the same nature, texture, and colour 

 as that of the respective beds themselves. In the same way at St. 

 Acheul, where there are beds of white and others of ochreous gravel, 

 the flint-implements exhibit corresponding variations in colour and 

 adhering matrix ; added to which, as the white gravel contains chalk 

 debris, there are portions of the gravel in which the flints are more 

 or less coated with a film of deposited carbonate of lime ; and so it is 

 with the flint-implements which occur in those portions of the 

 gravel. Further, the surface of many specimens is covered with fine 

 dendritic markings. Some few implements also show, like the 

 fractured flints, traces of wear, their sharp edges being blunted. In 

 fact, the flint-implements form just as much a constituent part of 

 the gravel itself — exhibiting the action of the same later influences 

 and in the same force and degree — as the rough mass of flint frag- 

 ments with which they are associated. 



With regard to the geological age of these beds, the author refers 

 them to those usually designated as post-pliocene, and notices their 

 agreement with many beds of that age in England. The Menche- 

 court deposit much resembles that of Fisherton near Salisbury ; the 

 gravel of St. Acheul is like some on the Sussex coast ; and that of 

 Moulin Quignon resembles the gravel at East Croydon, Wandsworth 

 Common, and many places near London. The author even sees 



