198 
ZOOLOGICAL GEOGRAPHY. 
[PART III. 
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 (S orex rusticus). 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 
again 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 (Cants 
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, ninety-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 Paltearctic 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 borealis (closely allied 
to the common wren, found also in the Faroe Islands) ; Fadco 
islandicus (closely allied to F. gyrfalco)\ Lagopus islandorum 
(closely allied to L. rupestris of Greenland), 
2. European species resident in Iceland. — Emberiza nivalis , 
Cw'vrn corax, Haliceetus albicilla , Radius aquaticus, Hcematopus 
ostralegus , Cygnusferus, Mergus (two species), Phalacocorax (two 
