LECTURE X. 287 



relation of the strata to each, other is more evident^ permits us 

 to determine the period to which they belong ; and^ on the 

 other hand, this comparison with those in Belgium, England, 

 and Holland points out to us the place they occupy in the 

 series of deposits of this period. 



" We may, therefore, with Worsaae, distinguish two stone 

 periods. The one, antediluvian, characterised by rudely hewn 

 flints, precedes these last quaternary deposits ; the second, 

 the later or pre-historic period, the weapons and implements of 

 which indicate a less barbarous condition, comprehends the 

 time when the population in Denmark accumulated the kitchen- 

 middens, and that of Switzerland, Ireland, and other regions 

 built the pile works." 



The reader is now, from these extracts from Elie de Beau- 

 mont, Hebert, and d'Archiac, enabled to draw his own conclu- 

 sion. As far as I am concerned, I am glad to find that I, 

 simultaneously with d'Archiac, and quite independently, have 

 arrived at the same results, namely : that the appearance of 

 man on the continent (independent of Desnoyers^ discoveries, 

 which were then unknown to us) occurred in the period after 

 the deposit of the boulder-clay. 



You may easily imagine that the search for stone hatchets 

 and flint tools as found in the valley of the Somme, extended 

 soon to other parts. Similar discoveries were presently made 

 in other spots. If I preferentially mention those made by 

 G-osse in the neighbourhood of Paris, the reason is, that the 

 stratification has been closely examined and determined. 

 Charles D'Orbigny thus describes the section of the diluvium 

 at Joinville, about six miles from Paris : — 



Upon the fresh water chalk of St. Ouen, which belongs to 

 the tertiary formation, rests a layer of about two meters, 

 seventy centimeters in thickness, of so-called grey diluvium, 

 with granitic pebbles, intermixed with large erratic blocks, in 

 which, besides bones of mammals and teeth of the mammoth 

 and rhinoceros, are found fragments of sea- and river-shells 

 from the subjacent tertiary cretaceous strata. Upon this grey 

 diluvium reposes a bed of white marly sand, about seventy 

 centimeters thick, in which are found marly knolls, as in the 



