Flint with Bivalves Mimachlamys cretosa fossile. It spanned the interval from 72.1 to 66 million years ago.
<a href="//commons.wikimedia.org/wiki/User:Erik_Christensen" title="User:Erik Christensen">Erik Christensen</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>