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No Idea found in Austin, TX


Leslie from Austin

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These were found at Mary Seaholm Park in South Austin in early March. I have no idea what any of it is. I suspect the darker things in front are iron ore. They're very heavy. The other things are in a soft, chalky matrix & seem very delicate. Any help would be great!

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That large chunk of rock has several calcite Inoceramus clams fragments. 

I found similar looking fragments in the Austin Chalk layer in the DFW. 

 

 

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I believe that the white, striated, blocky mineral is gypsum.  I agree that the dark rocks are iron concretions. 

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1 hour ago, grandpa said:

I believe that the white, striated, blocky mineral is gypsum.  I agree that the dark rocks are iron concretions. 

Gypsum can look like that but you find it as layers.  These are indeed "Inoceramus" shell fragments as Creek Don suggests. The prismatic shell structure/preservation is indicative of those big molluscs.  Scattered pieces like this can be very common in the Austin Group formations.  Eventually you will run into some bigger chunks that suggest the actual shell shape and even ones with borings, oyster spat or colonies of Pseudoperna congesta. 

 

Check out this page and website: http://oceansofkansas.com/Inoceramids.html

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Thanks, everyone! I'm excited to have my first Inoceramus clam fossil! I'm still uncovering more of it. I found this webpage also that has interesting information about shell growth:

 

https://www.researchgate.net/figure/Inoceramids-from-Sites-1260-and-1261-a-Fragment-of-a-shell-with-a-small-bivalve_fig2_240489553

 

And, I was wondering if these pieces (pics below) are an imprint of said clam?

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Lori, this likely an iron based pseudomorph of the pyrite nuggets common to the chalk formations that produce the Inoceramid fragments.  It could be limonite or hematite.

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The human mind has the ability to believe anything is true.  -  JJ

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The "Blob" looking thing looks like maybe some of these stuck together.

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