Bone fossil? What kind? Colorado, USA

[JLee]

Here is a rock/fossil from Moffat co. Colorado USA. Any ideas if it is a bone fossil? If so, what might it be from? It was found on the surface of a very rugged old road with no other similar looking rocks in sight. I did find a fossilized shell not far away (20 m). 

Edited June 25, 2022 by JLee

[val horn]

I dont think it is a bone because what should be trabecular bone is too irregular.  The round hole suggests acetabulum but that should be dense cortical bone and the balance of the shape does not seem right.

[HuckMucus]

It looks like a regular rock to me. The only reason I say the following is because you said it was the only one around:  Depending on how comfy it fits in your hand, it could be a capstone (socket) for a bow and drill kit.  Take a close look at that black in the pocket and see if it looks heat-related.

[JLee]

Ah, thank you both. Now being armed with the correct search terms, I can see it is likely related to fire starting. It definitely is possible that's where the black marks come from in the "socket." It is oddly comfortable to hold. I will "catch and release" this one! 

[HuckMucus]

6 minutes ago, JLee said:

Ah, thank you both. Now being armed with the correct search terms, I can see it is likely related to fire starting. It definitely is possible that's where the black marks come from in the "socket." It is oddly comfortable to hold. I will "catch and release" this one! 

Personally, I'd keep it and make a kit.  It's hard to tell if some Indian made it (though I'm not sure the black would have lasted this long; they had flint/steel for a long time) or some modern person, but if it works for making a fire, cool.

[JLee]

Good point about the black remaining. Thanks for the insight! It would be fun to learn to use.