e
fossil skeleton of a vertebrate, or the remains of an arthropod, the
more complete will be our conception of the form of the extinct
organism. It may be misleading in the numerous cases of convergence and
of generalized forms which now abound in our palaeontological
collections. We can well understand how guarded one must be in working
out the restorations of dinosaurs and fossil birds, of the Permian and
Triassic theromorphs, and the Tertiary creodonts as compared with
existing carnivora.

As the late O. C. Marsh[99] observed:

"We know to-day that unknown extinct animals cannot be restored from
a single tooth or claw unless they are very similar to forms already
known. Had Cuvier himself applied his methods to many forms from
the early tertiary or older formations he would have failed. If, for
instance, he had had before him the disconnected fragments of an
eocene tillodont he would undoubtedly have referred a molar tooth to
one of his pachyderms, an incisor tooth to a rodent, and a claw bone
to a carnivore. The tooth of a Hesperornis would have given him no
possible hint of the rest of the skeleton, nor its swimming feet the
slightest clue to the ostrich-like sternum or skull. And yet the
earnest belief in his own methods led Cuvier to some of his most
important discoveries."

Let us now examine from Cuvier's own words in his _Discours_, not
relying on the statements of his expositors or followers, just what he
taught notwithstanding the clear utterances of his older colleague,
Lamarck, whose views he set aside and either ignored or ridiculed.[100]

~ ~ ~ ~ ~

He at the outset affirms that nature has, like mankind, also had her
intestine wars, and that "the surface of the globe has been much
convulsed by successive revolutions and various catastrophes."

As first proof of the revolutions on the surface of the earth he
instances fossil shells, which in the lowest and most level parts of the
earth are "almost everywhere in such a perfect state of preservation
that even the smallest of them retain their most delicate parts, their
sharpest ridges, and their finest and tenderest processes."

"We are therefore forcibly led to believe not only that the sea has
at one period or another covered all our plains, but that it must
have remained there for a long time and in a state of tranquillity,
which circumstance was necessary for the formation of deposit