198 ZOOLOGICAL GEOGRAPHY. [part hi. 



insularity, have sufficed to commence the work of specific 

 modification. There are also a few small land-shells and several 

 insects not yet found elsewhere than in Britain ; and even one 

 of the smaller Mammalia — a shrew (Sorcx msticus). These facts 

 are all readily explained by the former union of these islands 

 with the Continent, and the alternate depressions and elevations 

 which are proved by geological evidence to have occurred, by 

 which they have been more than once separated and united 

 a^ain in recent times. For the evidence of this elevation and 

 depression, the reader may consult Sir Charles Lyell's Antiquity 

 of Man. 



Iceland is the only other island of importance belonging to 

 this sub-region, and it contrasts strongly with Great Britain, 

 both in its Arctic climate and oceanic position. It is situated 

 just south of the Arctic circle and considerably nearer Green- 

 land than Europe, yet its productions are almost wholly European. 

 The only indigenous land mammalia are the Arctic fox {Canis_ 

 lagopus), and the polar bear as an occasional visitant, with a 

 mouse {Mus islandicus), said to be of a peculiar species. Four 

 species of seals visit its shores. The birds are more interesting. 

 According to Professor Newton, uinety-five species have been 

 observed ; but many of these are mere stragglers. There are 

 twenty-three land, and seventy-two aquatic birds and waders. 

 Four or five are peculiar species, though very closely related to 

 others inhabiting Scandinavia or Greenland. Only two or 

 three species are more nearly related to Greenland birds than to 

 those of Northern Europe, so that the Pala3arctic character of 

 the fauna is unmistakable. The following lists, compiled from 

 a paper by Professor Newton, may be interesting as showing 

 more exactly the character of Icelandic ornithology. 



1. Peculiar species. — Troglodytes horcalis (closely allied 

 to the common wren, found also in the Faroe Islands) ; Falco 

 islandicus (closely allied to F. gyr falco) ; Lagopus islandorum 

 (closely allied to L. rupcstris of Greenland). 



2. European species resident in Iceland. — Emheriza nivalis, 

 Corvus corax, Haliceetus albicilla, Ballus aquaticus, Hmmatopus 

 ostralegus, Cygnus fcnis, Mergus (two species), Phcdacocorax (two 



