Leslie from Austin Posted May 14, 2020 Share Posted May 14, 2020 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! Link to comment Share on other sites More sharing options...
Creek - Don Posted May 14, 2020 Share Posted May 14, 2020 That large chunk of rock has several calcite Inoceramus clams fragments. I found similar looking fragments in the Austin Chalk layer in the DFW. 4 Link to comment Share on other sites More sharing options...
grandpa Posted May 14, 2020 Share Posted May 14, 2020 I believe that the white, striated, blocky mineral is gypsum. I agree that the dark rocks are iron concretions. 1 Link to comment Share on other sites More sharing options...
erose Posted May 14, 2020 Share Posted May 14, 2020 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 3 Link to comment Share on other sites More sharing options...
Leslie from Austin Posted May 14, 2020 Author Share Posted May 14, 2020 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? 1 Link to comment Share on other sites More sharing options...
GeschWhat Posted May 16, 2020 Share Posted May 16, 2020 I can't tell for sure, but this one looks like it might be an accumulation of invertebrate fossil fecal pellets. Can you post a close-up? 1 Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
JohnJ Posted May 16, 2020 Share Posted May 16, 2020 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. 1 The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
Leslie from Austin Posted May 16, 2020 Author Share Posted May 16, 2020 The "Blob" looking thing looks like maybe some of these stuck together. Link to comment Share on other sites More sharing options...
GeschWhat Posted May 16, 2020 Share Posted May 16, 2020 Yep, @JohnJ called it. I was thinking it could be something more like this. Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
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