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Pennsylvanian crinoid cup or sponge


gturner333

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I found this at Jacksboro, Texas, which is Jacksboro Limestone and Fines Shale from the Pennsylvanian. I thought it looked like a worn crinoid cup, possibly Graffhamicrinus, mainly because of the round holes in the top and bottom, the latter which may be the stem attachment. A friend suggested it was a sponge based upon some pictures in the Pennsylvanian Fossils of North Texas book put out by the Dallas Paleontological Society. I have attached pictures of the top and bottom and zoomed-in pictures of the holes. What do you think?

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I don't see the right texture for a sponge. I also don't see the 5 sides that the crinoid in the Pennsylvanian Fossils of North Texas book has. Are there other photos of Graffhamicrinus that you can show us, and have found on the internet, that look like you specimen?

My goal is to leave no stone or fossil unturned.   

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The basal view in Figure 4-63 on page 104 of the book mentioned above I thought looked like it. What else do you think it might be?

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I don't see the 5-sided symmetry in your specimen that is shown in the upper right photo of the oral view of a Graffhamicrinus cup in figure 4-63.

I also don't see in your specimen, the partial radial lines that extend to each of the 5 exterior corners of the cup and the lines that go from each exterior corner of the 5 sides to the nearest corner.

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My goal is to leave no stone or fossil unturned.   

See my Arizona Paleontology Guide    link  The best single resource for Arizona paleontology anywhere.       

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I see what you are talking about. So, any ideas as to what it might be? Could it be just geologic and still have the two hole patterns and be convex on one side and concave on the other? i.e. one of those darn suggestively shaped rocks?

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Perhaps an encrusting bryozoan, or algae.

It somewhat reminds me of these bryozoa I found.

Pennsylvanian, Virgilian series.

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Steve

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Gary, Pic 1 is the end off the mystery fossil that no one has identified.....has the same shape and has the "core" running through the middle. I have had some finger shaped that the end came off of, and they look the same....wish we could come to a consensus as to what they are.....

Thanks for your help in advance.

 

 

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