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minnbuckeye

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Locally, graptolites are very common in the Maquoketa/ Ordovician rock. They present themselves as 2 dimensional creatures on certain bedding planes. Below the Maquoketa is our Galena. It has graptolites but uncommon. Again, they present themselves as 2 dimensional. The "unknown" specimen from the Galena, presented today, is obviously 3 dimensional and I venture a guess that it is a Graptolite. But I thought I would seek opinions in that I have seen thousands of local graptolites but never one that is 3 dimensional. Could it be something else??

 

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27 minutes ago, Rockwood said:

Huh ! Not the usual look for their composition.

Replacements ? 

Phosphatic replacement.

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@Al Dente, I was surprised a Tar Heel had Iowa graptolites. If you came across these yourself, I am curious if they were loose or did you extract them from the Maquoketa bedrock? And were there 2 dimensional graptolites in the same layer?

 

 Mike

 

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These were found in a 6 inch thick layer where most of the fossils had phosphatic replacement. Other phosphatic fossils in the layer included small Hindia sponges, small nautiloids, various echinoderm ossicles, brachiopods and mollusks. The matrix was loose and easily screened. No 2 dimensional fossils in the layer.

22 minutes ago, minnbuckeye said:

@Al Dente, I was surprised a Tar Heel had Iowa graptolites. If you came across these yourself, I am curious if they were loose or did you extract them from the Maquoketa bedrock? And were there 2 dimensional graptolites in the same layer?

 

 Mike

 

 

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My first thought would be graptolite, too. But 3-dimensional preservation like that is not common! I wonder if that particular layer would qualify as a sort of lagerstatte? (konservat)

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  • 2 years later...

Unfortunately there is not much info on Galena graptolites. My best suggestion is possibly Diplograptus( Amplexograptus) maxwelli. Let me know your thoughts!!

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