CONCLUSION. 541 



must have been the state of Middle and Northern Europe when 

 Palaeolithic man hunted the reindeer in Southern France, and 

 when the arctic willow and its congeners grew at low levels in 

 Central Europe. Eefiect upon the fact that in the very same 

 latitude in France, where at one time the Canary laurel and the 

 fig-tree flourished, the pine, the spruce, and northern and high- 

 alpine mosses at another time found a congenial habitat. Bear 

 in view, also, that the land and freshwater molluscs testify 

 in like manner to the same strongly-contrasted climate. Besides 

 those that tell of more equable and genial conditions than the 

 present, there are species now restricted to the higher Alps and 

 northern latitudes that formerly abounded in Middle Europe, 

 and their shells occur commingled in the same deposits with 

 remains of lemmings, marmots, reindeer, and other northern and 

 mountain-loving animals. 



It is beyond doubt, therefore, that the fauna and flora of the 

 Pleistocene Period bear witness to great secular changes of 

 climate. Palaeolithic man lived in Europe along with many 

 southern mammals at a time when a singularly genial and 

 equable climate prevailed, and he was likewise a denizen of our 

 continent when conditions altogether different obtained. 



The appearances presented by the Pleistocene fluviatile 

 deposits testify to the same prime fact — they demonstrate that 

 the Palaeolithic Period was characterised by extraordinary 

 changes of climate. While some portions of the deposits in 

 question bespeak the action of such streams as now drain the 

 temperate regions of Europe — other parts indicate excessive 

 torrential force and imply the passage of enormously- flooded 

 rivers, and of broad sheets of inundation- water. More than this, 

 we often encounter in the gravels large stones and blocks which 

 could only have been transported by river-ice, and we may not 

 unfrequently note the occurrence of confused and crumpled 

 bedding in the same deposits, showing where the ice had packed 

 and run aground. The ancient river-deposits that cloak the sides 

 and bottoms of our valleys were laid down, as Mr. Prestwich 

 has shown, while those valleys were being slowly excavated— 



