石化した
animal
archaeological
archaeological dig
archeology
biology
calcarea
carbon fiber
discover
era
excavations
extinct
extinct animal
extinction
fossil
fossil animal
fossil sponge
fossilized
geological
geology
limestone
natural
nature
old
palaeontology
paleontology
petrified animal
petrified sponge
porifera
rock
sea
specimen
sponge
stone
urchin