Picked up at a rock shop

[mcwal10]

Hello all,

I'm not even sure if this is a fossil to begin with, as I'm an amateur fossil hunter. I found this piece in a rock shop called 'Prospector's Paradise', near the center of the Keweenaw Peninsula in Michigan. After talking to the shop owner, it sounds like it could have been found in the Northern part of the Keweenaw. It is possible that he did not find the piece himself, and could come from a different location. I apologize in advance, because it is not much to go on, and it's not a big deal if it can't be solved. The reason I thought it might be a fossil is because one side is smooth and rounded (like a ball-joint that might connect the humerus to the scapula), and because the parts that have been chipped off show a spongey interior (like a medullary cavity). It's possible that it's just a strangely shaped rock, but it would be exciting if it were some sort of fossil. Any help or suggestions would be much appreciated! 

[Paleostoric]

Reminds me of part of a tympanic bulla. Let's see what others have to say.

[val horn]

please show the other side

[mcwal10]

[Brett Breakin' Rocks]

16 hours ago, mcwal10 said:

that it's just a strangely shaped rock,

It's definitely bone .. it almost looks like a patella of some sort. Note the articulating surface on one side (concave) . Maybe these guys can recognize the hallmarks on the bone. @Shellseeker @Harry Pristis

 

Can we also get a shot of the bone in profile .. and a size reference ?  ie a ruler or measurement.

 

 

Cheers,

Brett

[mcwal10]

Here are a few more shots with a ruler for reference. Thanks to everyone who responded! 

 

[mcwal10]

[GPayton]

So I'm not very knowledgable about the geology of any state other than Texas, but after finding some geologic maps of Michigan online it seems like the youngest formations in the state are from the Jurassic period, however, most are from the Paleozoic era. Pleistocene fossils have been found on occasion, but really only in the southern portion of the state. The Keweenaw Peninsula in particular is entirely made up of Proterozoic/Pre-Cambrian bedrock, so there's no possible way this bone is actually from that location because not much besides single-celled animals existed back then. I thought at first that maybe it could have been found on the shore of Lake Superior since it could have drifted over from the Ontario side over time, but the northern shore of Lake Superior is part of the Canadian Shield and is made up of the same age rock as the Michigan side. 

At least to my eyes the bone looks Pleistocene-y, and is probably mammal based on the similarity to lots of bones I've found down near Houston that are similarly-aged, and because the porous inner structure of the bone hasn't filled in with minerals yet. Where it's actually from though, I have no clue. 

[Rockwood]

I think the title says it all. Someone picked it up in a rock shop and put it back in the wrong bin.

I suspect it is a fossil  (bulla?) that had been misplaced.

[pachy-pleuro-whatnot-odon]

Couldn't it be some kind of epiphyseal plate from a juvenile specimen of some sort? It reminds me of the articular surface of a long bone. And since these are not entirely epiphyseally fused in young animals that might explain why it's found as a separate piece of bone. That is, something along the line of the below, which shows the fusion stages for humans:

 

 

I guess I'm thinking more along the lines of @Brett Breakin' Rocks on this, as I too would, just by the look of the bone, think of Pleistocene material. At least, quite a bit of the Pleistocene material we find in the Netherlands looks similar to this.

[Rockwood]

Agreed. There are indications that the bone may be less dense than would be expected in a cetacean bulla.

[Shellseeker]

2 hours ago, pachy-pleuro-whatnot-odon said:

Couldn't it be some kind of epiphyseal plate from a juvenile specimen of some sort? It reminds me of the articular surface of a long bone. And since these are not entirely epiphyseally fused in young animals that might explain why it's found as a separate piece of bone. That is, something along the line of the below, which shows the fusion stages for humans:

 

Before I reached your post,  I was thinking about the socket femur_pelvic bones. A bone like this could easily come from the Pleistocene rich Peace River in Florida.

[LabRatKing]

Well, it's a Fragmentadon for sure.

As to which part of the anatomy....

 

<ramblings deleted as I disproved my own hypothesis>

 

Color is a lot like what we see out of the sandhills deposits in Nebraska and South Dakota, though Florida and Texas produce black bones like this too. (though we will likely never know the source).

[Mahnmut]

Hi and welcome to the Forum, Mcwal.

I think it may be rather a big animals small bone than the other way round because of its strange shape. Its fragmented, but not much so, there is much of the original surface.

Maybe some kind of carpal/tarsal bone or sesamoid like a patella?

Best regards,

J

[fossilus]

17 hours ago, mcwal10 said:

Hello all,

I'm not even sure if this is a fossil to begin with, as I'm an amateur fossil hunter. I found this piece in a rock shop called 'Prospector's Paradise', near the center of the Keweenaw Peninsula in Michigan. After talking to the shop owner, it sounds like it could have been found in the Northern part of the Keweenaw. It is possible that he did not find the piece himself, and could come from a different location. I apologize in advance, because it is not much to go on, and it's not a big deal if it can't be solved.

 

 

 

 

 

5 hours ago, Shellseeker said:

 

Before I reached your post,  I was thinking about the socket femur_pelvic bones. A bone like this could easily come from the Pleistocene rich Peace River in Florida.

 

It looks like Pleistocene bones from Texas also.

I believe the northern part of the keweenaw is really unlikely to have anything from the post paleozoic, unless very recent.  If you're sure it's fossilized, I think you were given bad provenance, and it could have come from anywhere.