472 Reviews — Schmff's Origin of the European Fauna. 



occur in Northern Europe and Nortli America, but are absent from 

 Asia, and he assumes the probability of a direct land-connection 

 between the two countries by way of Greenland before the Glacial 

 period, and a survival of these in Europe." 



Former Land-connection between Greenland, Scandinavia, and the 

 British Islands. — " I think it has been clearly shown that a former 

 land-connection must have existed between Scandinavia and 

 Greenland on the one hand, and between Scandinavia and the 

 British Islands on the other, and that it formed the highway for 

 an extensive migration from the north, and vice versa. Most 

 naturalists, indeed, admit this, but many deny that it could have 

 been anything but Post-Glacial, I believe that the migration took 

 place chiefly in later Pliocene times, i.e. during the deposition of the 

 newer Crags and of the Lower Continental Boulder-clay. The Arctic 

 animals and plants certainly reached the British Islands long before 

 the Siberian immigrants. Throughout the Glacial period (inclusive 

 of the period when the newer Crags were deposited) the White Sea 

 remained connected with the Baltic and the German Ocean, forming 

 the great sea which I ventured to call the Noi'th European Sea. 

 Long before the Arctic migration reached the British Islands, 

 another migration advanced from the south ; first, as I explained, 

 from South- Western Europe, and, as the climate became colder, 

 from Southern and Central Europe. Many of the animals and 

 plants which arrived with the latter straggled northward into 

 Scandinavia, and even at the present moment they seek to extend 

 their range in a northerly direction. There is no evidence that 

 their progress was checked by the Arctic climate, which is supposed 

 to have prevailed during the Glacial period." (p. 479.) 



The Southern Migration. — *' The bulk of the Irish fauna and 

 flora belongs to the Southern Migration, and we can divide its 

 members again roughly into those of South-Western and those of 

 Southern or Central European origin. But, in reality, the origin 

 of this migration is an exceedingly complex one, and is all the 

 more difficult to trace as migrations from the south to the north 

 have apparently proceeded uninterruptedly during many of the 

 past geological epochs — certainly during the whole of the Tertiary 

 era. Whilst most of the larger and short-lived forms have died 

 out again, some of the less conspicuous invertebrates are undoubtedly 

 of very ancient origin, and have witnessed vast changes in the 

 fauna and flora surrounding them. Many of these, though their 

 general distribution indicates a southern origin, baffle all attempts 

 at solving the problem of the location of their ancestral home. In 

 some respects the southern migration merges into the Siberian one ; 

 for there are a good many English species of animals and plants 

 which, though absent from Ireland, belong certainly to the former. 

 The dormouse (Muscardiniis avellanarius) , for instance, is probably 

 of Central European origin, but it nevertheless is absent from 

 Ireland.^ Its general range, however, proves that it is of very 



^ See on this point our criticism in the September number of the Geol. Mag. 

 on p. 421. 



