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will find that his method is neither more nor less than that of
Steno。 If he was able to make his famous prophecy from the jaw
which lay upon the surface of a block of stone to the pelvis of
the same animal which lay hidden in it； it was not because
either he； or any one else； knew； or knows； why a certain form
of jaw is； as a rule； constantly accompanied by the presence of
marsupial bones； but simply because experience has shown that
these two structures are co…ordinated。
The settlement of the nature of fossils led at once to the next
advance of palaeontology； viz。 its application to the
deciphering of the history of the earth。 When it was admitted
that fossils are remains of animals and plants； it followed
that； in so far as they resemble terrestrial； or freshwater；
animals and plants； they are evidences of the existence of land；
or fresh water； and； in so far as they resemble marine
organisms； they are evidences of the existence of the sea at the
time at which they were parts of actually living animals and
plants。 Moreover； in the absence of evidence to the contrary； it
must be admitted that the terrestrial or the marine organisms
implied the existence of land or sea at the place in which they
were found while they were yet living。 In fact； such conclusions
were immediately drawn by everybody； from the time of Xenophanes
downwards； who believed that fossils were really organic
remains。 Steno discusses their value as evidence of repeated
alteration of marine and terrestrial conditions upon the soil of
Tuscany in a manner worthy of a modern geologist。
The speculations of De Maillet in the beginning of the
eighteenth century turn upon fossils； and Buffon follows him
very closely in those two remarkable works； the 〃Theorie de la
Terre〃 and the 〃Epoques de la Nature〃 with which he commenced
and ended his career as a naturalist。
The opening sentences of the 〃Epoques de la Nature〃 show us how
fully Buffon recognised the analogy of geological with
archaeological inquiries。 〃As in civil history we consult deeds；
seek for coins； or decipher antique inscriptions in order to
determine the epochs of human revolutions and fix the date of
moral events； so； in natural history； we must search the
archives of the world； recover old monuments from the bowels of
the earth； collect their fragmentary remains； and gather into
one body of evidence all the signs of physical change which may
enable us to look back upon the different ages of nature。 It is
our only means of fixing some points in the immensity of space；
and of setting a certain number of waymarks along the eternal
path of time。〃
Buffon enumerates five classes of these monuments of the past
history of the earth； and they are all facts of palaeontology。
In the first place； he says； shells and other marine productions
are found all over the surface and in the interior of the dry
land； and all calcareous rocks are made up of their remains。
Secondly； a great many of these shells which are found in Europe
are not now to be met with in the adjacent seas； and； in the
slates and other deep…seated deposits； there are remains of
fishes and of plants of which no species now exist in our
latitudes； and which are either extinct； or exist only in more
northern climates。 Thirdly； in Siberia and in other northern
regions of Europe and of Asia； bones and teeth of elephants；
rhinoceroses； and hippopotamuses occur in such numbers that
these animals must once have lived and multiplied in those
regions； although at the present day they are confined to
southern climates。 The deposits in which these remains are found
are superficial； while those which contain shells and other
marine remains lie much deeper。 Fourthly； tusks and bones of
elephants and hippopotamuses are found not only in the northern
regions of the old world； but also in those of the new world；
although； at present； neither elephants nor hippopotamuses occur
in America。 Fifthly； in the middle of the continents； in regions
most remote from the sea； we find an infinite number of shells；
of which the most part belong to animals of those kinds which
still exist in southern seas； but of which many others have no
living analogues； so that these species appear to be lost；
destroyed by some unknown cause。 It is needless to inquire how
far these statements are strictly accurate； they are
sufficiently so to justify Buffon's conclusions that the dry
land was once beneath the sea； that the formation of the
fossiliferous rocks must have occupied a vastly greater lapse of
time than that traditionally ascribed to the age of the earth；
that fossil remains indicate different climatal conditions to
have obtained in former times； and especially that the polar
regions were once warmer； that many species of animals and
plants have become extinct； and that geological change has had
something to do with geographical distribution。
But these propositions almost constitute the frame…work of
palaeontology。 In order to complete it but one addition was
needed； and that was made； in the last years of the eighteenth
century； by William Smith； whose work comes so near our own
times that many living men may have been personally acquainted
with him。 This modest land…surveyor； whose business took him
into many parts of England； profited by the peculiarly
favourable conditions offered by the arrangement of our
secondary strata to make a careful examination and comparison of
their fossil contents at different points of the large area over
which they extend。 The result of his accurate and widely…
extended observations was to establish the important truth that
each stratum contains certain fossils which are peculiar to it；
and that the order in which the strata； characterised by these
fossils； are super…imposed one upon the other is always the
same。 This most important generalisation was rapidly verified
and extended to all parts of the world accessible to geologists；
and now it rests upon such an immense mass of observations as to
be one of the best established truths of natural science。 To the
geologist the discovery was of infinite importance as it enabled
him to identify rocks of the same relative age； however their
continuity might be interrupted or their composition altered。
But to the biologist it had a still deeper meaning； for it
demonstrated that； throughout the prodigious duration of time
registered by the fossiliferous rocks； the living population of
the earth had undergone continual changes； not merely by the
extinction of a certain number of the species which had at first
existed； but by the continual generation of new species； and the
no less constant extinction of old ones。
Thus the broad outlines of palaeontology； in so far as it is the
common property of both the geologist and the biologist； were
marked out at the close of the last century。 In tracing its
subsequent progress I must confine myself to the provi