Fossil or geological formation? Nooksack River, just east of Glacier, Wa

[mmcever]

I found this specimen in a gravel bed on the bank of the Nooksack River a few miles east of Glacier, Wa. The rock is dark gray, river smoothed, and dense. I have very little experience in this field and was hoping someone might be able to shed some light on what this might be. Any help is greatly appreciated.

 

 

 

 

 

 

 

 

 

 

 

 

[abyssunder]

Welcome to the Forum! 

Phothos suggest bones in matrix for me, especially the junksion seen on the third pucture.

[supertramp]

What a weird and interesting find.

…I suspect that those are subspherical or ellipsoidal shapes rather than sections of cylindrical structures.

Maybe I’m wrong, but, for example: do they match on two “opposite surfaces” as on the picture below (same colour)?

 

[mmcever]

On 8/11/2020 at 3:00 AM, supertramp said:

What a weird and interesting find.

…I suspect that those are subspherical or ellipsoidal shapes rather than sections of cylindrical structures.

Maybe I’m wrong, but, for example: do they match on two “opposite surfaces” as on the picture below (same colour)?

 

The colors you have marked do match up but I believe you are onto something about their shape. I have since found another similar piece that has the same circular pattern as seen on the previous find but the other end seems to be spherical/rounded. So perhaps they are somewhat cylindrical objects with rounded ends?

 

[abyssunder]

Maybe they are pisoids of a pisolitic mineral formation / pisolitic limestone?

[mmcever]

12 minutes ago, abyssunder said:

Maybe they are pisoids of a pisolitic mineral formation / pisolitic limestone?

 

 

Showing my ignorance here but I had to look up pisoids and the information/photos plus your photo certainly make it a possibility. My specimen doesn’t seem to have the concentric rings/tree rings that are talked about and I see in most photos but I certainly don’t know enough to rule it out. Thank you!

[abyssunder]

7 minutes ago, mmcever said:

 

Showing my ignorance here but I had to look up pisoids and the information/photos plus your photo certainly make it a possibility. My specimen doesn’t seem to have the concentric rings/tree rings that are talked about and I see in most photos but I certainly don’t know enough to rule it out. Thank you!

The number of rings are not constant. It could be only one ring, as I remember correctly.

[supertramp]

It’ a puzzle…I don't have an answer…but other questions I hope can help to find a solution; that’s a really weird item (I've never seen pisoids like these, Abyssunder, ciao).

So,

with regard to the type of rock:

- you could check if it reacts with diluted hydrochloric acid (not sure it’s limestone…not even that’s a sedimentary rock to be honest),

On 8/8/2020 at 9:41 PM, mmcever said:

The rock is (...) and dense.

- I would try to measure the density by immersion

 

Can you take a picture to show what this object looks like through the thickness of the sample?

 

Can you show the specimen of this picture from above?

 

...there are holes both in the center of the lighter objects and some others in the black matrix…don't know what that could mean.

Just a wild guess: some weird concretion (but what about the holes?)