Fossilised, petrified (8)
I believe the answer is:
ossified
This clue is a double definition.
'fossilised' is the first definition.
(I know that fossilised can be written as ossified)
'petrified' is the second definition.
(thesaurus)
(Other definitions for ossified that I've seen before include "Fossilised, petrified" , "If so, dies, being changed into bone" , "Made rigid and set into a conventional pattern" , "Turned to stone" , "Turned to bone with age" .)