Not what it appears to be
Despite its appearance, this is an ammonite not a snail. Look very closely at the small break in the shell and you’ll see the suture line, made where the internal chambered shell meets the outside of the shell. Ammonites from the Lower Chalk are very distinctive and developed into a range of bizarre forms. It’s thought that ammonites began to experience stress from climate change and that led them to evolve into a whole new range of forms. It didn’t do them much good though, as they became extinct at the end of the Cretaceous period, along with the dinosaurs and two thirds of life on the planet.