Belemniten Schlachtfeld 1

36x30x5cm. From the clay pit in Mistelgau, Bavaria. Jurensismergel Formation, uppermost Toarcian, lower Jurassic.

The "belemnite battlefield" is used in this area to mark the border between the Lower and Upper Toarcian. At the time of deposition, which occurred over a long stretch of time, this area was on a shallow shelf in a narrow straight between the Böhmischen Massiv (mainland in the east) and the Rheinisches Insel (island in the west). There was also possibly a threshhold bank called the Ries Schwelle to the south which rose above the water surface during regressive times. During and after this time, the deposits were condensed (phosphorite concretions) and were subject to intensive turbulent currents which again and again mixed and redeposited them. This caused the broken bits, cracks and roll marks on the rostren which can be seen. This layer is isochrone, which means it stretches over hundreds of square kilometers in the Franconian Alb. A Fischsaurier "cementary" was discovered a few years ago in these layers close to Esslingen which led the researchers to postulate a methane catastrophy as possible cause for the death of these creatures, but it's a controversial proposal as usual, and the death of the belemnites were nevertheless also due to more natural causes, since they were layed down long before as well as during and after the sudden death occurence of the Ichthyosauriers.