Learn how to say Fossilisation correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word fossilize:
preserve (an animal or plant) so that it becomes a fossil:
the hard parts of the body are readily fossilized
[no object] become a fossil:
flowers do not readily fossilize
become or cause to become fixed and incapable of change or development:
we want to see a working countryside—we don’t want to see it fossilized