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 (Sorex rusticus).. These facts 
are all readily explained by the former union of these islands 
with the Continent, and the alternate depressions and elevations 
which aré 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 (Canis 
lagopus), and the polar bear as an occasional visitant, with a 
mouse (Jus 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 Palzarctic character of 
the fauna is unmistakable. The foliowing lists, compiled from 
a paper by Professor Newton, may be interesting as showing 
more exactly the character of Icelandic ornithology. 
1. Peculiar species. —TZroglodytes borealis (closely allied 
to the common wren, found also in the Faroe Islands); Falco 
islandicus (closely allied to F. gyrfalco); Lagopus islandorum 
(closely allied to Z. rupestris of Greenland). 
2. European species resident in Iceland—Hmberiza nivalis, 
Corvus corax, Halicetus albicilla, Rallus aquaticus, Hamatopus 
ostralegus, Cygnus ferus, Mergus (two species), Phalacocorax (two 
