46 | Great Geologists
Illustrations of foraminifera by d’Orbigny for the Tableau méthodique
de la classe des Céphalopodes.
In 1846 he published his study of fossil foraminifera of the
Vienna Basin – a study that like so much of his work was grand
in scope and execution. Everything was included: systematics,
with the description of 228 species; stratigraphic distribution
(Paleozoic to Recent); paleoenvironmental interpretation
including possible generalized water temperature variations.
In particular, he made an argument for the use of foraminifera
in stratigraphic studies and correlation - “ils peuvent servir à
déterminer sûrement l’âge d’un terrain géologique” (they can be
used to determine the age of a geological interval with certainty)
- something that is taken for granted today and a vital tool for
correlatiing rocks at outcrop and in the subsurface. In the earlier
Jurassic ammonites illustrated by d’Orbigny for Paléontologie
Française (1842).
Chalk Memoir he had written “the comparative study of fossil
foraminifera of all zones has proved to me a fact of geological
importance: it is that each zone has its characteristic species, by
which it may be recognized in whatever circumstances that can
occur: and these little shells being infinitely more common than
those of Mollusca, the application of them which we can make is
so much the more certain and becomes extremely interesting.”
The later years of his life he devoted to his monumental
“Prodrome de Paléontologie stratigraphique des animaux
Mollusques rayonnés,” an attempt to place fossils in
stratigraphic context and to “Cours élémentaire de paléontologie