Great Geologists | 27
the last appearing in 1832 at
His study of the
the time of Cuvier’s death.
comparative anatomy of
living creatures naturally
This study of geological
brought his attention to
history, punctuated by rapid
fossils, initially extinct
environmental change, led
vertebrates. In 1796,
Cuvier to suggest that Earth’s
he recognised that an
history had been episodically
engraving of a huge fossil
interrupted by sudden
skeleton from South
‘revolutions’ that caused
America, housed in the
the extinction of existing
royal museum in Madrid,
fauna. Such ideas were first
was an extinct giant
documented in Discours
sloth, which he named
Préliminaire of his great work
Megatherium (“huge
of 1812, Recherches sur les
beast”). Soon afterwards
Ossemens Fossiles, which
he demonstrated that
was later published separately
fossil mammoth bones
as Discours sur les Révolutions
and teeth from Siberia,
de la surface du Globe and
The fossil specimen that Cuvier recognised as a flying reptile -
although similar to
which became known as
Ptero-dactyle.
elephants from Asia and Africa,
the definitive catastrophist
belonged to a separate, extinct
view of geological history.
species. He determined that the
Ultimately these views came into conflict with Charles Lyell’s
spectacular skull of a huge fossil animal from a chalk quarry in
uniformiatarism, a steady-state view of Earth history.
Maastricht had belonged to a large marine lizard (now called
Mosasaurus) and a small fossil reptile skeleton from Jurassic
The impact of Discours upon early 19th century science was
strata in Bavaria was that of a flying reptile, which he called
profound. Here was an attempt to elucidate a history of the
Ptero-dactyle. Such determinations were made possible by
Earth that went beyond the observations and correlations of his
Cuvier’s detailed understanding of the anatomical function
British contemporaries such as William Smith. While Smith may
of the bones preserved, from which he inferred the nature of
have expressed the power of fossils for stratigraphic subdivision,
a complete creature and its mode of life. Most importantly,
correlation and mapping slightly ahead of Cuvier and Brongniart,
Cuvier recognised the existence of creatures that were not
it was Cuvier who first attempted to determine the history of our
living today, which for him gave evidence of worlds previous to
planet through the vastness of geological time. Cuvier’s views
todays, inhabited by creatures very different to those around us.
can be summarised by this translated paragraph:
Extinction was a real feature of the natural world, so to explain
“Life upon the earth in those times was often overtaken
this required consideration of the geological past.
by these frightful occurrences. Living things without
Accordingly, Cuvier’s geological interests rapidly expanded
number were swept out of existence by catastrophes.
beyond the determination of the nature of fossils. In
Those inhabiting the dry lands were engulfed by deluges,
collaboration with the mineralogist Alexandre Brongniart, in
others whose home was in the waters perished when the
1811 he presented Essai sur la géographie minéralogique des
sea bottom suddenly became dry land; whole races were
environs de Paris, which contained not only a geological map
extinguished leaving mere traces of their existence, which
of the Paris Basin, but a stratigraphic synthesis in the form of
are now difficult to recognise, even by the naturalist. The
a novel sedimentary log. In the manner of William Smith in
evidences of those great and terrible events are everywhere
Britain, they used the fossil content of the strata for subdivision
to be clearly seen by anyone who knows how to read the
and correlation. Moreover, they determined a succession of
record of the rocks.”
alternating freshwater and marine environments — a pioneering
It is hard not to draw an analogy between Cuvier’s view of
attempt to reconstruct the geological history of the succession.
geological history and the revolutionary nature of contemporary
The two men progressively refined their stratigraphic
politics in Europe, especially France where, at the end of the
understanding with more detailed logs, maps and descriptions,