their
peculiarities afford us an important clue to some of the most efficient
means of distribution among several classes of animals.

* * * * *

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CHAPTER XII

OCEANIC ISLANDS:--THE AZORES AND BERMUDA

THE AZORES, OR WESTERN ISLANDS

Position and Physical Features--Chief Zoological Features of the
Azores--Birds--Origin of the Azorean Bird Fauna--Insects of the
Azores--Land-Shells of the Azores--The Flora of the Azores--The
Dispersal of Seeds--Birds as Seed-Carriers--Facilities for Dispersal of
Azorean Plants--Important Deduction from the Peculiarities of the
Azorean Fauna and Flora.

BERMUDA

Position and Physical Features--The Red Clay of Bermuda--Zoology of
Bermuda--Birds of Bermuda--Comparison of the Bird Faunas of Bermuda and
the Azores--Insects of Bermuda--Land Mollusca--Flora of
Bermuda--Concluding Remarks on the Azores and Bermuda.

We will commence our investigation into the phenomena presented by oceanic
islands, with two groups of the North Atlantic, in which the facts are of a
comparatively simple nature and such as to afford us a valuable clue to a
solution of the more difficult problems we shall have to deal with further
on. The Azores and Bermuda offer great contrasts in physical features, but
striking similarities in geographical position. The one is volcanic, the
other coralline; but both are surrounded by a wide expanse of ocean of
enormous depth, the one being about as far from Europe as the other is from
America. Both are situated in the {247} temperate zone, and they differ
less than six degrees in latitude, yet the vegetation of the one is wholly
temperate, while that of the other is almost tropical. The productions of
the one are related to Europe, as those of the other are to America, but
they present instructive differences; and both afford evidence of the
highest value as to the means of dispersal of various groups of organisms
across a wide expanse of ocean.

THE AZORES, OR WESTERN ISLANDS.

These islands, nine in number, form a widely scattered group, situated
between 37deg and 39deg 40' N. Lat. and stretching in a south-east and
north-west direction over a distance of nearly 400 miles. The largest of
the islands, San Miguel, is about forty miles long, and is one of the
nearest to Europe, being rather under 900 miles from the coast of Portugal,
from which it is separated by an ocean 2,500 fathoms deep.