Old Black Bone with Amber Marrow. Is this considered a Dinosaur Gem Bone? Or??

[vscience]

Check out photos. What would you call it? I think this is a fossilized black bone with yellow /amber marrow in center. So, I wonder if it is a dinosaur gem bone.
It is approx. 3 inches and quite heavy - almost 4 ounces. There is some white shell stuck to it so it must have been in the water. I recently acquired it with a handful of similar items in Florida. Any identification input would be helpful. Thanks

 

[Jason in Enid]

That doesn't look like the interior of any fossilized bone I have ever seen before.

 

[Age_old]

Looks like a dugong rib fragment, a common find here in Florida. Marine mammals have dense bones to counteract buoyancy, that's why there is no sponge bone in the center.

 

[Harry Pristis]

Dugong rib fragments are an abundant fossil in Bone Valley. The black specimen with adherent shell material probably came from off-shore Venice Beach.

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[vscience]

Awesome. You folks are amazingly knowledgeable! Thanks for the info.