kozman
noticing nice landscape pebbles
Member since July 2020
Posts: 83
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Post by kozman on Aug 28, 2020 18:29:10 GMT -5
A pentagon fossil imprint? Found this on shoreline Lake Michigan beach just south of Milwaukee. Maybe a plant stem slice?
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Post by rockpickerforever on Aug 28, 2020 19:33:50 GMT -5
A pentagon fossil imprint? Found this on shoreline Lake Michigan beach just south of Milwaukee. Maybe a plant stem slice?
I believe it is a crinoid stem. They have a variety of shapes: I've seen some pentagon shaped crinoid stems, but the majority of the ones found here in the SoCal desert are round. Individual pieces may be found, but more likely you see several together, reminding one of stacked poker chips. The stem holds up the crown. The stem pieces are more likely to fossilize than the crowns. At least, I have never found a fossilized crown in all my searching. They are an extinct animal (not a plant) in the class Crinoidea, one of the classes of the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. A common fossil found in Paleozoic-age marine rocks.
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Post by Pat on Aug 28, 2020 20:16:22 GMT -5
I thought this was a joke!! I immediately recognized the white sink drain on an old crust of a French bread, surrounded by lumpy whipped cream!!
I guess not ...
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Post by hummingbirdstones on Aug 28, 2020 21:59:48 GMT -5
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Post by Pat on Aug 28, 2020 23:06:11 GMT -5
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Post by jasoninsd on Aug 29, 2020 5:10:28 GMT -5
I second hummingbirdstones... PatBut to be fair...I didn't see it until you pointed it out...and it does!
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Post by hummingbirdstones on Aug 29, 2020 9:19:58 GMT -5
I saw it right away, too. So funny!
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Post by rockpickerforever on Aug 29, 2020 18:16:05 GMT -5
You're welcome! Dentist? Ouch, why did you try to eat it! Olive pits seem to be my nemesis, lol. Your ID of the fossil in the photo above is exactly right. Great find! I have only seen photos of them. There are some great fossil hunting grounds in the desert an hour's drive to the east of us. The area has been under water many times over the years, as a northern extension to the Gulf of Mexico, as a fresh water lake (ancient Lake Cahuilla), a shallow saltwater sea, and it also received rocks and fossils from points north via the ancient Colorado River. A plethora of neat stuff to find. Have even found a camel vertebrae a toe bone.
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kozman
noticing nice landscape pebbles
Member since July 2020
Posts: 83
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Post by kozman on Aug 29, 2020 21:57:41 GMT -5
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Post by rockpickerforever on Aug 29, 2020 22:36:56 GMT -5
You are correct, sir! Some on them are still living. Brittle stars, starfish (echinoderms), and sea urchins are still extant. Funny, I guess I don't think of starfish as crinoids, but they are related. So crinoids are not extinct, but the ones still living are not like the ones of 250 million years ago. When checking into this, one website I looked at, said horn corals are not extinct - wrong! They are deader than a doornail, having been dead for over 250 million years. Crinoids came close to extinction around that same time, toward the end of the Permian Period. The end of the Permian was marked by the largest extinction event in the history of life.
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kozman
noticing nice landscape pebbles
Member since July 2020
Posts: 83
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Post by kozman on Aug 30, 2020 20:32:04 GMT -5
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Post by rockpickerforever on Aug 30, 2020 20:56:02 GMT -5
From Fossilifera, About Crinoids. LINK
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,666
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Post by Fossilman on Aug 31, 2020 10:13:59 GMT -5
Many fossil "Cousins" are living creatures still to this day....
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