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| The first words that come to mind when describing these extinct marine
animals are squid-like, torpedo shaped molluscs. When the belemnite is being
fossilized, commonly only the bullet shaped shell (or guard) is found, but
some belemnites have been found with flesh imprints in the shell. The blunt
end of the guard possibly surrounded the reduced chamber shell. The shell
extended forwards to protect the body. belemnites had two lateral fins, a large head, well developed eyes, with many tentacles covered with hooks, to catch prey. The guard (shell) might have been used as a ballast device. They swam, as modern day squid and octopi do, by jet propulsion. They lived from the Carboniferous period ( which started 365 million years ago) and survived until the Oligocene ( 36 million years ago)- so they survived for 329 million years- that's pretty good going! You can find belemnites in all marine sedimentary rock, but they are most common in Jurassic and Cretaceous layers. The fossil in the picture was found on Whitby beach, in North Yorkshire, England. |