Pavlovia pallasioides Neaverson.
Beautifully preserved 3D ribbed Ammonite with original white shell intact. half way around the outer whorl there is an irregular hole in the shell. There are a number of possible reasons for this. The Ammonite's shell has could have exploded due to build up of gas after death. Alternatively, it may be the result of an injury sustained in an attack from a predator resulting in the death of the Ammonite.
Jurassic, Upper Kimmeridge Clay, Pallasioides Zone.
Chapman's Pool, Kimmeridge Bay, Dorset.
Ammonite : 4.5 cm diam.