84 The Scottish Naturalist. 



tenable. He concludes, therefore, with Sir J. Lubbock, that the com- 

 mingling of discordant forms in the Pleistocene deposits implies former 

 changes of climate. When the hippopotamus was a native of Yorkshire, 

 the conditions in North-western Europe were mild and genial ; when the 

 reindeer and its northern associates occupied the low grounds of Southern 

 France, and the glutton and the marmot frequented the coast-lands of the 

 Mediterranean, the climatic conditions of Europe must have been extremely 

 severe. The testimony afforded by the Pleistocene flora is strikingly cor- 

 roborative of this conclusion. It proves to us that during the Pleistocene 

 period several very great changes of climate must have occurred. Thus we 

 find that at one time there flouiished near Paris a flora that comprised the 

 fig, the judas-tree, the Canary laurel, laurustinus, and other plants ; while 

 at another epoch of the same period the prevailing character of the flora 

 in Northern France was more northern than it is at the present day. In 

 Central and Southern Europe similarly contrasted floras are met with in the 

 Pleistocene deposits. Thus at Canstadt we encounter an assemblage of 

 plants analogous to that discovered near Paris ; while in the low grounds of 

 Switzerland, and various regions in Germany, we come upon an arctic-alpine 

 flora, containing the arctic willow, the dwarf birch, and other northern and 

 high-alpine forms ; and along with these, insects of northern habitats not 

 unfrequently occur. In Southern Europe the contrasts between the floras of 

 the Pleistocene are, as might have been expected, not so strongly marked. 

 A flora betokening a singularly genial and equable climate is common in 

 many deposits in Southern Fiance and Italy ; but we also meet with sug- 

 gestive botanical evidence in favour of much less genial conditions having 

 formerly prevailed. Thus the Siberian pine occurs in the peat-bogs of Ivrea, 

 and the Scots fir in those near the Lake Varese. The testimony of the mol- 

 luscs points in precisely the same direction as that of the mammals, the insects, 

 and the plants. From the lists of species, and the references given by Dr 

 Geikie, we gather that the evidence furnished by the plants and molluscs 

 is much more abundant than probably many geologists are aware ; and we 

 may hope that those osteologists who think to work out the historical geology 

 of the Pleistocene from a consideration of the mammalian evidence alone, 

 will hereafter pay greater attention to the other palreontological evidence 

 than they have hitherto done. Just as there are two more or less strongly 

 contrasted floras met with in the Pleistocene deposits, so there are very dis- 

 similar groups of molluscs. Thus in the neighbourhood of Paris the Canary 

 laurel and its congeners are associated with many shells, some of which are 

 still indigenous, some extinct, while many others are restricted to more 

 southern regions. In similar latitudes, again, a large proportion of the 

 Pleistocene molluscs are northern and high-alpine forms. Even so far south 

 as the neighbourhood of Lyons, northern forms preponderate in certain 

 Pleistocene accumulations ; while in Corsica the shells met with in the 

 Pleistocene breccias suggest a colder and wetter climate than that lovely 

 island now enjoys. So far, then, as the paloeontological evidence goes, it 

 demonstrates that during the Pleistocene Period when Palaeolithic man occu- 

 pied our continent, very considerable changes of climate supervened ; and 

 the closing stage of that period, corresponding to the so-called "Reindeer 

 epoch," was extremely severe, — an arctic-alpine flora then occupying the 

 low grounds of Central Europe, while northern mammals ranged south to 



