Bone, branch, root or other?

[AmadorGreg]

Found this on 11/11/21 hiking near the shore of Lake Camanche in Amador County, CA.  Camanche is a reservoir fed by the Mokelumne River and is pretty low this year, exposing some good rock hunting spots.  Last year a ranger with EBMUD discovered fossils of mastodon, camel, horse and more in this watershed.  We found lots of petrified wood and this one item that to me looks like a tibia or fibula because of the ridges that slowly spiral around it.  All of the petrified wood was much lighter on the outside I believe from calcite.  This item didn't have any of that on the outside, was much darker and splintery looking, like a chicken bone.  Inside there does seem to be some calcite and there was some sandstone that I sprayed out before the picture.

 

It is 6" long and 2" wide and is hard as a rock and heavy, just like petrified wood.  The center is hollow on one end but solid on the other.  I would think a branch or root would be hollow more consistently from end to end.  And the hollowness is quite wide, if this was a branch it would be very weak.  It was near the shore of the lake with a bunch of other random rocks.  Further away from the shore are lots of sedimentary rock cliffs that I believe are caliche.

 

I am very new to all of this so I may not be observing things correctly, most of what I just said I've learned just in the last couple days researching online.  Would be great to know if it's a bone or not, and even possibly from what animal!

 

Lake Camanche satellite view and spot where item was found attached as well.

 

 

[Rockwood]

1 hour ago, AmadorGreg said:

great to know if it's a bone or not

Well, you're in for it is. The fracture pattern shown on the end sure looks like it would be a fossil too.

[Ludwigia]

I'm by far no expert on these matters, but is there any chance that this might be a piece of horn?

[Quriosity]

Wood wouldn't be empty at the core like this. So I would go for fossil bone. A piece of horn unlikely, there seems to be a kind of ridge on it.

[Rockwood]

3 hours ago, Ludwigia said:

piece of horn?

The bony core, may I assume ?

[Rockwood]

3 hours ago, Quriosity said:

Wood wouldn't be empty at the core like this

Never worked with a lot of cedar ? Balsam fir if you need a garden planter scale. They are commonly hollow.

[Quriosity]

On 11/14/2021 at 3:20 PM, Rockwood said:

Never worked with a lot of cedar ? Balsam fir if you need a garden planter scale. They are commonly hollow.

The smoothness inside seemed a bit too much for wood, but I may have been mistaken.

 

A close-up of the surface and a picture of the other cross-section would help.

[AmadorGreg]

Here are some more detailed (and blurry) pics and cross section from other side, now that it is dry.  The triangular shape looks like a fibula cross section.

 

 

 

 

 

 

[Plax]

this is bone for me with the marrow rotted out before replacement.

[AmadorGreg]

Would leaving it in a citric acid bath for a few hours help clean it up?