Geoscience Reference
In-Depth Information
considered to be one of the most important globally for the study of
Silurian rocks. Alicide Dessalines d'Orbigny (1802-1857), a remark-
able French naturalist and traveller, published during his short life a
number of very important works onMesozoic and Cenozoic fossils, of
which in the present context his Prodrome de pale´ontologie stratigra-
phique universelle (1850-1852) was the most valuable. D'Orbigny
highlighted some difficult fossil groups and he paid particular attention
to microscopic organisms including Foraminifera, unicellular animals
that continue to inhabit the world's oceans. It was later shown that
these microfossils had great biostratigraphical potential. In the United
States important monographic series included Palaeontographica
Americana published since 1916 by the Paleontological Research
Institute of New York, and in Germany Palaeontographica, which
commenced publication in 1846.
Students in the mid to late 1800s had access to a plethora of
palaeontological information, and could either consult the primary
monographs or resort to a new source of secondary material, the
palaeontological textbooks. Of these the Traite
´
e
´
le
´
mentaire de
pale
´
ontologie (1844-1846) by Fran¸ois Jules Pictet (1809-1872), the
Manual of Palaeontology by Henry Alleyne Nicholson (1844-1899)
which first appeared in 1872, and the Grundzu¨ge der Palaeontologie
by Karl Alfred von Zittel were probably the most comprehensive and
therefore the most useful. The German text was first published in
1895 in Munich, and an English edition (Text-book of Palaeontology)
followed in 1902 and remained in print for at least thirty years.
Geologists were now armed with the raw ingredients with which to
apply biostratigraphical analysis.
MARKER FOSSILS, OR BIOZONES
Smith developed a crude biostratigraphy, but thanks to the numerous
studies in the thirty years following his work biostratigraphical preci-
sion was tightened up considerably. In Germany two palaeontologists
made the study of Jurassic ammonites their lives' work. Ammonites
are extinct molluscs that are members of the Class Cephalopoda, a
