fossilised

ˈfɒs(ə)lʌɪz
ˈfɒsɪlʌɪz

verb

preserve (an animal or plant) so that it becomes a fossil.

the hard parts of the body are readily fossilized

petrified,ossified,lapidified,archaic,antiquated,antediluvian,old-fashioned,quaint,outdated,outmoded,behind the times,anachronistic,stuck in time,prehistoric,antwacky