Ammonoid Presentation

Natural History/Geology

1. Ammonites and Belemnites

2. 1. Ammonites
The Ammonoid is a common example of cephalopod mollusc fossil.
The Ammonoid existed in an marine environment
Specimens are found in sedimentary rocks such as limestone and chalk rocks.
Ammonoid Fossils are found in a rock strata dated between the Devonian [416-359 million years] to the end of the
Cretaceous [65.5 m years]
The outer shell is marked by a pattern of grooves termed Suture, this feature strengthened the shell.
Below is a Fossilized Shell specimen
Euhoplites

3. 2. The Fossilization cycle

4. 3. Cephalopod Class

5. Belemnites
The extinct Belemnite sub order [ >65.5 M Yrs] is an example of Coleoid fossil. Specimens are found in
Jurassic & Cretaceous Geology.

6. Belemnites

7. Belemnite Fossils
The photographed examples are the remains of a skeletal guard.
The biological term for this structure is the Rostrum
These Rostrum fossils were derived from a resistant calcium carbonate structure
The guard fossils have a narrow elevation and sharp prominence similar to a Javelin.
The Rostrum shielded the lower mantle of a belemnite.
Clusters of fossilized Belemnite guards can be perceived to mirror the sight of a lightening strike.
Belemnitella

8. References
http://www.paleodirect.com

The Encyclopaedia of Palaeontology Rhodes
Whitmore Fairbridge, David Jablonski 1979 Page 72
Photography and Identification.