Brazos River Pleistocene puzzler

[garyc]

This was found on the Brazos river in southeast Texas. It almost looks like a eroded shell material, but I cannot make out at all what it is. Could this be a coprolite? I have never found one before, so I have no idea what a coprolite would look like in this area.

[Brandy Cole]

Hey Gary, could you get some pictures with some better light?  It looks like it could be a piece of ironstone to me. That shine and shape reminds me of some ironstone I've found.  But better pictures to show texture and color would help.

[garyc]

Thanks @Brandy Cole I’ll try to get some sun lit pic’s tomorrow if there’s a break in the rain. I know what you mean about iron stone, but I’ve not seen one like this

[Brandy Cole]

Well @garyc, based on the weather here today, I'm betting the clouds weren't cooperating where you are!

 

The only other thought I had is that I occasionally find rocks with marine shell deposits in them, but those deposits are typically very light colored compared to the much darker rocks that carry them. The shell outlines are also much smaller than what you have here. 

 

Have you tried a vinegar test?  If the dark part is ironstone, then I'd assume the light brown part is sandstone filler that should fizz if you put some vinegar on it.

[garyc]

So, vinegar did nothing. @Brandy Cole I know what you mean about iron stone, but this does not look like any ironstone that I’ve found on the Brazos. Here are some more pics that I hope are better

[Brandy Cole]

It's a very interesting piece!

 

Unfortunately I think the camera is showing more detail on the table than your specimen.  Could you try pulling back the camera some to see if it helps the focus?

 

I'm wondering if it isn't some mineral veining running through a metamorphic rock.

[garyc]

I think these are the best pictures that I can possibly get. I hope it helps. I am a little curious about this piece.

[fossilus]

I'm wondering if it could be some silicified Cretaceous?

Edited January 6, 2023 by fossilus

[JohnJ]

4 minutes ago, fossilus said:

I'm wondering if it could be some silicified Cretaceous?

 

It certainly looks like a shell hash.

[JBkansas]

Could we get an in focus picture of the round button like structure on the end. It looks a little like a crinoid stem disc?

Edited January 6, 2023 by JBkansas

[Rockwood]

Oysters and/or gastropods most likely.

[garyc]

2 hours ago, JBkansas said:

Could we get an in focus picture of the round button like structure on the end. It looks a little like a crinoid stem disc?

This is the best I can do

[garyc]

I think @fossilus and @JohnJ are correct. I do find cretaceous oysters quite frequently on the Brazos. This little conglomerate of hash threw me off. Thanks for looking y’all!