f distinct continents." That is to say, the differences
are usually confined to species and genera, whereas in the case of
continents the differences extend to orders. Similarly in marine
productions the same laws prevail--the species on the different sides of
the American continent, for instance, being very distinct. Now, this law
cannot be explained by any reasonable argument from design.

And still stronger does the present argument become when we look to the
fossil species contained on different continents; for these fossil
species invariably present the same characteristic stamp as the living
species now flourishing on the same continents. Thus, in America we find
fossils all presenting the characteristically American types of animals,
in Australia the characteristically Australian types, and so on. That is
to say, on every continent the dead species resemble the living species,
as we may expect that they should, if they are all bound together by the
ties of hereditary descent; while, if different continents are compared,
the fossil species are as unlike as we have seen the living species to
be.

Turning next to the case of oceanic islands, situated at some distance
from a continent. In these cases the plants and animals found on the
island, though very often differing from all other plants and animals in
the world as regards their specific type, nevertheless in generic type
resemble the plants and animals of the neighbouring continent. The
inference clearly is, that the island has been stocked from the
continent with these types--either by winds, currents, floating trees,
or numerous other modes of transport--and that, after settling in the
island, some of these imported types have retained their specific
characters, while others have varied so as to become specific types
peculiar to that island. The Galapagos Archipelago islands are
particularly instructive in this connection; for while the whole group
of islands lies at a distance of over five hundred miles from the shores
of South America, the constituent islands are separated from one another
by straits varying from twenty to thirty miles. Now, to quote from
Darwin, "Each separate island of the Galapagos Archipelago is tenanted,
and the fact is a marvellous one, by many distinct species; but these
species are related to each other in a very much closer manner than to
the inhabitants of the American continent." That is to say, the
American continent being some