the same way
the existence of identical structural roots, if I may so term them,
entering into the composition of widely different animals, is striking
evidence in favour of the descent of those animals from a common
original.

To turn to another kind of illustration:--If you regard the whole
series of stratified rocks--that enormous thickness of sixty or seventy
thousand feet that I have mentioned before, constituting the only record
we have of a most prodigious lapse of time, that time being, in all
probability, but a fraction of that of which we have no record;--if you
observe in these successive strata of rocks successive groups of animals
arising and dying out, a constant succession, giving you the same kind
of impression, as you travel from one group of strata to another, as
you would have in travelling from one country to another;--when you find
this constant succession of forms, their traces obliterated except to
the man of science,--when you look at this wonderful history, and ask
what it means, it is only a paltering with words if you are offered the
reply,--'They were so created.'

But if, on the other hand, you look on all forms of organized beings as
the results of the gradual modification of a primitive type, the facts
receive a meaning, and you see that these older conditions are the
necessary predecessors of the present. Viewed in this light the facts of
palaeontology receive a meaning--upon any other hypothesis, I am unable
to see, in the slightest degree, what knowledge or signification we are
to draw out of them. Again, note as bearing upon the same point, the
singular likeness which obtains between the successive Faunae and
Florae, whose remains are preserved on the rocks: you never find any
great and enormous difference between the immediately successive Faunae
and Florae, unless you have reason to believe there has also been a
great lapse of time or a great change of conditions. The animals, for
instance, of the newest tertiary rocks, in any part of the world, are
always, and without exception, found to be closely allied with those
which now live in that part of the world. For example, in Europe,
Asia, and Africa, the large mammals are at present rhinoceroses,
hippopotamuses, elephants, lions, tigers, oxen, horses, etc.; and if
you examine the newest tertiary deposits, which contain the animals
and plants which immediately preceded those which now exist in the same
country, you do not find gigan