Travertines, gypsum, and tufa 

 (not tuff 10 ), indicating a dry, semi- 

 ^arid to arid climate, not necessarily 

 volcanic disturbance. 



CORRELATION OF THE TIME DIVISIONS 457 



Sheet of "lower loess" [cor- 

 responding with the arid period of 

 late -cool- Acheulean] . 



Upper tufa levels, with flora of 

 box (Buxus), fig-tree (Ficus), 

 Canary laurel (Laurus noMlis), in- 

 dicating a climate somewhat milder 

 or more temperate than in the same 

 region at the present time. 



Middle tufa levels containing 

 early Acheulean implements, dis- 

 covered in 1893-1894. 



Lower tufa levels containing 

 sycamore-maple (Acer pseudopla- 

 tanus), willows, and pine, indicat- 

 ing a temperate climate. Pleistocene 

 river grayels of 30-meter terrace. 



Villefranche-sur-Saone, near Lyons. — This horizon, so much discussed 

 and so badly interpreted by many prehistorians, seems to be at the bottom 

 of a terrace of 30 meters. At one point it retains its normal altitude, at 

 another point, where it has undergone secondary erosion, it actually rises 

 only a few meters above the Somme Eiver. A thick covering of loess 

 rests on these fluviatile sands; what remains of the loess contains 

 numerous flints belonging either to the pure late Acheulean or to the 

 time of transition between the Acheulean and the Mousterian. 



Acheulean Arrival in Belgium 



Horizon of Sainte-Walburge in the Hesbayen loess. — The conclusions 

 arrived at by the veteran archeologist, Marcel de Puydt, and his able 

 colleagues, J. Hamal-Nandrin and Jean Servais (1912.1), are as follows: 



"Conclusions. — La presence de silex tailles dans les alluvions de Liege nous 

 amene aux conclusions suivantes : 



"1° Le depot de la rue Jean de Wilde n'est pas eolien, du moins pour la partie 

 qui renferme les silex tailles. 2° Le depot n'a pas ete produit par une inonda- 

 tion. 3° Dans l'etat actuel de nos connaissances, il ne peut avoir ete constitue 

 que par ruissellement. 4° Cette hypothese du ruissellement rend compte des 

 differences notables que presentent en Hesbaye deux coupes voisines. 

 5° L'homme et la faune quaternaire ont habite notre pays alors que les vallees 

 principales etainent presque totalement creusees. Le relief du sol etait done 

 alors sensiblement le meme qu'aujourd'hui et n'a plus ete modifie depuis que 

 d'une maniere insignifiante. 6° L'arrivee de l'homme quaternaire est 

 posterieure a la formation des terrasses superieures on moyennes dans la 



10 Tuff, to geologists, is a volcanic ash deposit which is observed about an explosive 

 type of volcano following a violent eruption. 



