The Rise and Progress of Palaeontology | Page 9

and the second is, that the stratified rocks in which they are
found are sedimentary deposits; and each of these propositions is
founded upon the same axiom, that like effects imply like causes. If
there is any cause competent to produce a fossil stem, or shell, or bone,
except a living being, then palaeontology has no foundation; if the
stratification of the rocks is not the effect of such causes as at present
produce stratification, we have no means of judging of the duration of
past time, or of the order in which the forms of life have succeeded one
another. But if these two propositions are granted, there is no escape, as
it appears to me, from three very important conclusions. The first is that
living matter has existed upon the earth for a vast length of time,
certainly for millions of years. The second is that, during this lapse of
time, the forms of living matter have undergone repeated changes, the
effect of which has been that the animal and vegetable population, at
any period of the earth's history, contains certain species which did not
exist at some antecedent period, and others which ceased to exist at
some subsequent period. The third is that, in the case of many groups
of mammals and some of reptiles, in which one type can be followed
through a considerable extent of geological time, the series of different
forms by which the type is represented, at successive intervals of this
time, is exactly such as it would be, if they had been produced by the
gradual modification of the earliest forms of the series. These are facts
of the history of the earth guaranteed by as good evidence as any facts

in civil history.
Hitherto I have kept carefully clear of all the hypotheses to which men
have at various times endeavoured to fit the facts of palaeontology, or
by which they have endeavoured to connect as many of these facts as
they happened to be acquainted with. I do not think it would be a
profitable employment of our time to discuss conceptions which
doubtless have had their justification and even their use, but which are
now obviously incompatible with the well-ascertained truths of
palaeontology. At present these truths leave room for only two
hypotheses. The first is that, in the course of the history of the earth,
innumerable species of animals and plants have come into existence,
independently of one another, innumerable times. This, of course,
implies either that spontaneous generation on the most astounding scale,
and of animals such as horses and elephants, has been going on, as a
natural process, through all the time recorded by the fossiliferous rocks;
or it necessitates the belief in innumerable acts of creation repeated
innumerable times. The other hypothesis is, that the successive species
of animals and plants have arisen, the later by the gradual modification
of the earlier. This is the hypothesis of evolution; and the
palaeontological discoveries of the last decade are so completely in
accordance with the requirements of this hypothesis that, if it had not
existed, the palaeontologist would have had to invent it.
I have always had a certain horror of presuming to set a limit upon the
possibilities of things. Therefore I will not venture to say that it is
impossible that the multitudinous species of animals and plants may
have been produced, one separately from the other, by spontaneous
generation; nor that it is impossible that they should have been
independently originated by an endless succession of miraculous
creative acts. But I must confess that both these hypotheses strike me as
so astoundingly improbable, so devoid of a shred of either scientific or
traditional support, that even if there were no other evidence than that
of palaeontology in its favour, I should feel compelled to adopt the
hypothesis of evolution. Happily, the future of palaeontology is
independent of all hypothetical considerations. Fifty years hence,
whoever undertakes to record the progress of palaeontology will note

the present time as the epoch in which the law of succession of the
forms of the higher animals was determined by the observation of
palaeontological facts. He will point out that, just as Steno and as
Cuvier were enabled from their knowledge of the empirical laws of co-
existence of the parts of animals to conclude from a part to the whole,
so the knowledge of the law of succession of forms empowered their
successors to conclude, from one or two terms of such a succession, to
the whole series; and thus to divine the existence of forms of life, of
which, perhaps, no trace remains, at epochs of inconceivable
remoteness in the past.
FOOTNOTES
(1) De Solidoiintra Solidum, p.5--"Dato corpore certa figura
praedito et juxta leges naturae producto, in ipso corpore