fossilise
1. [ verb ] become mentally inflexible
Synonyms: fossilize
Related terms: age fossilization
2. [ verb ] convert to a fossil
Synonyms: fossilize
Examples:

"The little animals fossilized and are now embedded in the limestone"

Related terms: convert lapidify fossilization
Similar spelling:   fossilised
  fossilize
  fossilist
  fossilized
  focalise
  fossil_copal