580 W. BOYD DAWKINS ON THE EXISTENCE OP 



New Comers. Extinct species. — 6. 



Ursus spelseuS; Gold}'. Elephas antiquus, Falc. 



Cervus verticornis, Dawk. Arvicola intermedius, Newt. 



Elephas primigenius, Boj. Caprovis Savinii, Newt* 



From the examination of this list it will be seen that out of 39 

 species, twelve belong to the Pliocene strata of Prance and Italy, 

 while 27 are to be counted as immigrants and, with three exceptions 

 ( Cervus verticornis, Caprovis Savinii, and Arvicola intermedius), as 

 common late Pleistocene forms. It is obvious therefore that the 

 line of division between the Pliocene and Pleistocene must be drawn 

 so as to include the Forest-bed within the latter. The additions made 

 to the fauna by Mr. E. T. Newton and others since the publication 

 of my memoir f on classification in 1872 have confirmed the accu- 

 racy of this conclusion, and have further proved that the arctic 

 mammalia were then in the valley of the North Sea. It is not a 

 little strange that the musk-sheep and the glutton, two animals now 

 living side by side in North America, should appear together in 

 Britain. They undoubtedly were driven so far south at this time 

 by the gradual lowering of the temperature, which has left its mark 

 in the Forest-bed strata by the replacement of the cold-temperature 

 trees of the Forest-bed proper by stunted types peculiar to cold 

 climates, and by the appearance of Arctic species such as Salix 

 jpolaris and Hypnum turgescens %. 



8. General Conclusio7is. 



The following conclusions may be drawn from the foregoing 

 observations : — First that the Musk-sheep invaded Britain from 

 the continent, along with the rest of the North-Asiatic animals 

 characteristic of the Pleistocene area, before the glacial conditions 

 of climate had set in in the area of the eastern counties ; secondly, 

 that it was living in the valley of the Severn after the glacial con- 

 ditions had disappeared from that area. It most probably arrived 

 at the southern limits of its range on the continent while the cold 

 was at its height in Britain, and swung northwards again as the 

 cold diminished. In other words it may be said to be pre-, inter-, and 

 post-glacial in Europe. Lastly it may be gathered from the large 

 number of living species of mammalia in the Forest-bed that the 

 phenomena summed up under the head of glacial do not form a hard 



house. The species occurs in the Pliocene strata of Auvergne. See Dawkins, 

 " Contributions to the History of the Deer of the European Miocene and 

 Pliocene Strata," Quart. Journ. Geol. Soc. 1878, p. 416. 



* From these lists I have omitted all the doubtful forms and more especially 

 the fragmentary antlers, which await future identification. For an admirable 

 account of the Vertebrates of the Forest-bed, see E. T. Newton, " The Vertebrates 

 of the Forest-bed series," Mem. Geol. Survey, 1882. To the lists hitherto 

 published I have added three forms, the Ovibos moschatus, the Cervus tetra- 

 ceros, and the Hycena spelcea, the last of which is in the collection of Mr. 

 Backhouse. 



t Quart. Journ. Geol. Soc. Nov. 1872. 



$ Nathorst, in Lyell, ' Antiquity of Man,' 4th edit. p. 262. 



