GOSSIP ON ANTIQUITY OF MAN. 93 



bones bound together by their natural ligaments, of the co- existence 

 of man with mammals since extinct. It further appears that the 

 waters at first must have been propelled through these channels 

 with great force, and thus accumulated the stony fragments — that 

 succeeding this torrent there was a regular current, and that then 

 fine mud and bones accumulated — and that when this stayed the 

 stalagmite floor was gradually formed. 



I might point to other instances of cavern deposits, which seem 

 to corroborate the received chronology with reference to the age of 

 man, which I find no valid reason for carrying back to remoter 

 periods. I shall however rest this part of the case with the facts 

 quoted, and proceed to examine my theory by the evidence afforded 

 by river deposits, containing bones of extinct mammalia and flint 

 implements similar to those of the caves. 



It must be borne in mind that these alluvial deposits in valleys, 

 are made up of erosions and denudations of the surface strata, and 

 are similar to those which are found in caverns. We ought there- 

 fore to have the same phenomena — or with slight modifications — in 

 both ; and it is so. The same inverted strata meet us here openly, 

 which met us in the underground passages and caves communicating 

 with the surface. In the diagram* before you, w^hich is a section 

 across the valley of the Somme in Picardy, you will find the regu- 

 lar order of superposition of strata — first the chalk (I), next the 

 eocene strata (2), then the loam, or drift, or brick earth (3). Next 

 you will find the upper and lower level gravels made up of denu- 

 dations, which I have marked — upper (2 a), and lower (3 «) ; then 

 the gravel bed (4), the peat (5), and the river Somme, as it now 

 runs, (6). I will read the description (with these figures) from Sir 

 Charles Lyell's book, and afterwards make a short commentary 

 upon it, in accordance with my own views . — 



" The valley of the Somme in Picardy is situated geologically 

 in a region of white chalk with flints, the strata of which are nearly 

 horizontal. The chalk hills which bound the valley are almost 

 everywhere between 200 and 300 feet in height. On ascending to 

 that elevation we find ourselves on an extensive table land, in which 

 there are slight elevations and depressions. The white chalk itself 

 is scarcely ever exposed at the surface on this plateau, although 



♦ This is copied from the section in Sir Charles Lyell's book, and is not correct, 

 but will give an idea of the position of the various deposits. (See section.) 



