bunnyfights
noticing nice landscape pebbles
Member since May 2022
Posts: 83
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Post by bunnyfights on May 4, 2022 14:29:53 GMT -5
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nursetumbler
Cave Dweller
Member since February 2022
Posts: 928
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Post by nursetumbler on May 6, 2022 7:17:15 GMT -5
Hi
I am new so I can't help you BUT as a nurse it reminds me of cut end of a bone after amputation. Maybe it is an ancient bone that filled in with chalcedony? Pretty cool whatever is. 🙃
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,456
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Post by Sabre52 on May 6, 2022 8:38:08 GMT -5
Looks kind of like a little limb cast to me. We occasionally find agate limb casts in association with limestone and chert here in Texas.
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Post by rmf on May 6, 2022 15:24:03 GMT -5
In SW WI the rocks are Ordovician and that would predate limb casts. Typical marine fossils like coral. The problem with chert is that as it forms it removes a lost of the diagnostic detail. What counties in WI. My geologic training was in the rocks from Dane Co south and west. Plus the Baraboo Syncline.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,456
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Post by Sabre52 on May 6, 2022 17:34:30 GMT -5
Oh heck yeah, way too early for a limb cast in chert. We're all mostly lower cretaceous here. That's a stumper. I've never seen many fossils from that period at all. Wonder if there were any boring mollusks that would leave a tunnel as a trace fossil or if that is a partial filled in shell of one of the early cephalopods with the long pointy tube-like shell. A lot of our chert nodules in limestone here are infillings of old voids often left by shells or erosion creating all kinds of weird shaped nodules. Also many of the crinoids from that period were stalked and quite large. Could be you have a stem section where every detail of the original structure was lost and only a tube shape remained to be filled with silica. Quite a fun mystery.
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