(notwithstanding crossing) where good breeds of dogs and pigs have been
introduced into a limited country,--for instance, into the islands of
the Pacific.

{399} This instance occurs in the Essay of 1842, p. 32, but not in
the _Origin_; though the importance of isolation is discussed
(_Origin_, Ed. i. p. 104, vi. p. 127).

{400} The meaning of the words within parenthesis is obscure.

{401} It is unusual to find the author speaking of the selection of
_sports_ rather than small variations.

Let us now take the simplest natural case of an islet upheaved by the
volcanic or subterranean forces in a deep sea, at such a distance from
other land that only a few organic beings at rare intervals were
transported to it, whether borne by the sea{402} (like the seeds of
plants to coral-reefs), or by hurricanes, or by floods, or on rafts, or
in roots of large trees, or the germs of one plant or animal attached to
or in the stomach of some other animal, or by the intervention (in most
cases the most probable means) of other islands since sunk or destroyed.
It may be remarked that when one part of the earth's crust is raised it
is probably the general rule that another part sinks. Let this island
go on slowly, century after century, rising foot by foot; and in the
course of time we shall have instead <of> a small mass of rock{403},
lowland and highland, moist woods and dry sandy spots, various soils,
marshes, streams and pools: under water on the sea shore, instead of a
rocky steeply shelving coast, we shall have in some parts bays with mud,
sandy beaches and rocky shoals. The formation of the island by itself
must often slightly affect the surrounding climate. It is impossible
that the first few transported organisms could be perfectly adapted to
all these stations; and it will be a chance if those successively
transported will be so adapted. The greater number would probably come
from the lowlands of the nearest country; and not even all these would
be perfectly adapted to the new islet whilst it continued low and
exposed to coast influences. Moreover, as it is certain that all
organisms are nearly as much adapted in their structure to the other
inhabitants of their country as they are to its physical conditions, so
the mere fact that a _few_ beings (and these taken in great degree by
chance) were in the first case transported to the islet, would in itself
greatly modify their conditions{404}. As