From the Jurassic,Sinemurian stage.
Collected from Lyme Regis,Dorset,England.
A complete Arnioceras ammonite from the Lower lias,collected back in the 1950s
These can be unstable unless treated,but i purchased this from an old collection,so its clearly lasted over 70 years without any issues!
The ammonite is loose from matrix and measures 45mm.