Location: North Yorkshire Coast (found on beach)

Class: Ammonoid

Sub Class: ??????

Age: Jurassic

Shape: Evolute

Mode: Nektonic, free swimming buoyancy achieved using air chambers

 

Fossil shown is actually 5 inch wide, and found as an erratic on the beach.

This is what's called a trace fossil, and unfortunately does not show enough of the trace fossils casting to identify Ammonitida.

Careful removal of sedimentation has a good chance of revealing more fossils, which might make this an interesting specimen.