This gastropod fossil is called Euthriofusus complanatus. It was named by James De Carle Sowerby. The snail is also known as Wrigleya complanata. It was found in the London Clay of Highgate, North London England. The fossil dates to the lower Eocene Epoch (Ypesian) of the Paleogene Period.
It was on display at the British Natural History Museum in London on August 2016.
Learn more: https://en.wikipedia.org/wiki/London_Clay