Mystery bone

[Henry T]

Okay folks. This one, I have no clue. The information that was given to me was nominal. That being Western United States, purchased at an Estates sale. I, by all means, am not looking for an exact identification. I'm trying to figure out 1)why is it so dark?/ 2)Dino. versus post dino. mammal? 3)What part of the creature? I'm guessing distal extremity.

 

Thanks!

 

 

 

[Tidgy's Dad]

When organic matter decays it often will turn darker with the chemical changes. 

Chemicals may also be leached from the bone and replaced with other, darker, minerals. 

Or the bones may be stained by dyes from sediments.  

[Auspex]

The coloration is due to the minerals in the entombing sediment.

As for narrowing-down an ID, my comfort level for this one ends at Subphylum: Vertebrata.

[Troodon]

Very difficult to determine what you have without a more specific locality and there is nothing diagnostic about you bone.  May be a vertebra and cannot rule out dinosaurian.  The color like Tidgy's Dad said is a result of the minerals in the sediment and a good example is that whitish Plesiosaur vertebra you just posted.   Its fossilized in the Phosphate beds of Khouribga. 

[Henry T]

Thank you for the info.