Before preparation 1/3
Before preparation 2/3
Before preparation 3/3
During preparation 1/2
During preparation 2/2
The finished specimen
This trilobite was found inside a glacial erratic from the coast of the Baltic Sea in northern Germany. The erratic was transported by the glaciers from Scandinavia to Heiligenhafen during the Ice Age and deposited there. Ogmasaphus praetextus occurs relatively frequently in this type of rock, although well-preserved and complete ones are rare. This specimen is an exuvia, which can be recognised by the slight disarticulation and the missing right librigena. The last picture shows the finished specimen at the site of discovery, the coast of Heiligenhafen.
The preparation of trilobites from these hard and splintery limestones is very challenging. Usually the rock separates rather badly from the shell, which is very thin and fragile. Parts of the shell have been lost while breaking the stone, which were restored in the course of the preparation (see photos).
Fossil: Ogmasaphus praetextus TÖRNQUIST 1884
Locality: Heiligenhafen, Germany
Formation: Upper Ordovician, Ludibundus-Kalk
Length of the trilobite: 4,7 cm (1.85 inches)
Work required: 22 hours
Collection: Tim Haye