Cross section of the fossil: note the calcite-chambers in the centre
Cross section of the fossil: note the calcite-chambers
in the centre
All parts were glued and the fossil successfully roughed out
All parts were glued and the fossil
successfully roughed out
The finished specimen after 18 hours of work
The finished specimen after
18 hours of work
Presenting the Discoceras and explaining the preparation-process
at a conference in the Natural History Museum Berlin.
Presenting the Discoceras and explaining
the preparation-process at a conference
in the Natural History Museum Berlin.
Discoceras fossils are relatively common in ordovician erratics (“Macrouruskalk”) of Northern Germany. In most cases however, their remains are incomplete, more or less crushed and/or badly preserved. In contrast, complete and well-preserved specimens are very rare. The piece presented here is an absolute exception. The preservation is very good and even the living chamber is largely intact.
The preparation of these Ordovician nautiloid fossils is difficult, because the limestone is not only very hard, but also has very poor separation. In addition, the shell is almost always partly dissolved and therefore very fragile. When all parts of the fossil are carefully collected and the preparation is done with patience and caution, extremely attractive results like this one can be achieved.
Fossil: Discoceras danckelmanni (REMELÉ, 1890)
Locality: Cliff near Rerik (Germany)
Formation: Middle Ordovician, Macrouruskalk
Diameter: 11cm (4.3 inch)
Work required: 18 hours
Collection: Jan Tädcke
This Discoceras and its preparation process were presented in 2019 at the 18th conference for “Geschiebeforschung” (glacial erratics research) in the Natural History Museum Berlin:
Paul Freitag & Jan Tädcke: Vom Fund zum fertigen Ausstellungsstück: Porträt eines Discoceras aus einem Macrouruskalk-Geschiebe. Link zur Tagung: https://www.geschiebekunde.de/02-11-bis-03-11-2019-18-berliner-tagung-fuer-geschiebeforschung/