CLIMATE OF PLEISTOCENE PERIOD. 51 



France the box at present hardly passes north beyond the 

 environs of Lyons, and certainly does not grow spontaneously 

 north of the rocky plateau of the Cote d'Or, 1 the broad-leaved 

 spindle-tree is arrested at the Jura, the judas-tree does not 

 occur north of Montelimart, the fig-tree is not indigenous beyond 

 Provence, and the Canary laurel exists in a wild state, as already 

 stated, only near Toulon, in the most southern part of the 

 Department of Yar. Mingled with all these species are others 

 which serve to distinguish the flora of Moret from that of the 

 tufas of Southern France. Among these is the sycamore (Acer 

 pseudo-platanus), a tree of Central and Northern Europe, which 

 occurs in the Alps but does not extend south into the Mediter- 

 ranean region, where its place is taken by Acer opulifolium, 

 Vill. It is widely spread in the shady woods of Central and 

 Northern France, of Switzerland, and Germany. This tree, the 

 relics of which occur plentifully in the tufa of La Celle, cannot 

 be grown successfully in Provence, where many attempts have 

 been made to introduce it. It languishes under the hot dry 

 summer of the south, and very rarely reaches an adult stage. 

 The common ash is another of the trees which, like the syca- 

 more, is no longer associated with those southern forms along 

 with which it formerly grew in Northern France. It is almost 

 excluded from the Mediterranean region, but abounds in Central 

 France, and extends north to Southern Sweden. In the tufas 

 of Southern France and Italy its place is taken by the manna- 

 ash (Fraxinus ormis, L.) Now this very remarkable assemblage 

 of plants tells a tale which there is no possibility of misreading. 

 Here we have the clearest evidence of a genial, humid, and 

 equable climate having formerly characterised Northern France. 

 The presence of the laurel, and that variety of it which is most 

 susceptible to cold, shows us that the winters must have been 

 mild, for this plant flowers during that season, and repeated 

 frosts, says Saporta, would prevent it reproducing its kind. It 

 is a mild winter rather than a hot summer which the laurel 

 demands, and the same may be said of the fig-tree. The olive, 



1 According to Hooker the box is indigenous in Belgium. 



