By a modern species I mean one which is currently extant upon the Earth.
A creature that died 10,000 years ago will not be mineralized to nearly the same extent as a million year old fossil.
So why is it that we find no dinosaur “bones” that are actually bone? Why are they all so extensively mineralized, but we don't see, for example, an elephant fossil mineralized to nearly the same extent?
If dinosaurs and elephants were contemporaneous, why do we never see an elephant fossil that ‘appears’ to be 50 million years old, or dinosaur fossils that ‘appear’ to only be a few thousand years old?
How do you know we never find elephant bones mineralized to the same extent?