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More Black Shale Finds from West Virginia - What are they?


Kurri Kline

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Here are a few things I would love to know what they are:

 

#1 Black shale that we used years ago to make a decorative siding for the barn, what are those shallow pits? This rock is about 7 inches long.

#2 This came from a different area in the Eastern Panhandle that was near a large creek.

#3 Same thing as #2?  

 

Thank you for your help!

1.jpg

2.jpg

2a.jpg

3.jpg

3a.jpg

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Not sure about 1, some closer pics would help. 2 and 3 have impressions of crinoid stems and brachiopods or bivalves, unclear which.

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2 hours ago, connorp said:

Not sure about 1, some closer pics would help. 2 and 3 have impressions of crinoid stems and brachiopods or bivalves, unclear which.

In total agreement. Just to be clear the round ones are crinoid impressions and the shell looking ones are brachiopods or bivalve impressions. If you can find a shell imprint that looks whole you can tell which it is based on the symmetry of the shell and begin to determine more from there. (As a general rule brachiopods look symmetrical when looking at one side straight on and bivalves look symmetrical when looking at the seam between the shells)

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The pits I believe could be described as conchoidal fractures. The shale looks to be metamorphosed. That could have disrupted the way it cleaves.

I don't have a great degree of confidence in either idea though. Just trying to get things started.

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I agree with all of the posters above.

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Looking at the 2nd picture of item #3, I'm curious about the star-shaped item sitting at the 11:00 position above the crinoid stem impression.  Any ideas what this is?

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1 minute ago, grandpa said:

Looking at the 2nd picture of item #3, I'm curious about the star-shaped item sitting at the 11:00 position above the crinoid stem impression.  Any ideas what this is?

I would think it is a very worn crinoid ossicle/columnal impression. 

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12 minutes ago, grandpa said:

Any ideas what this is?

I think it's a nodal that had cirri attached to it. A cirrinodal if you will.

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@Rockwood, I'm inclined to agree with you and @Fossildude19.  To further elaborate and combine the two thoughts, we're looking at the edge of a crinoid ossicle which has a cirus attachment scar (node) exposed.  Have I understood correctly what you are proposing? 

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20 minutes ago, grandpa said:

@Rockwood, I'm inclined to agree with you and @Fossildude19.  To further elaborate and combine the two thoughts, we're looking at the edge of a crinoid ossicle which has a cirus attachment scar (node) exposed.  Have I understood correctly what you are proposing? 

 

I believe that is the case. :) 

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41 minutes ago, grandpa said:

Have I understood correctly what you are proposing? 

No.

The way I see it we are looking at a mold of a columnal with casts of the lumen which led to the cirri radiating toward its center. The central lumen must have been small with a restricted opening connecting it to the cirri. At least that is the best way I can explain why the lumen in the center wasn't cast the same way.

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5 hours ago, Rockwood said:

No.

The way I see it we are looking at a mold of a columnal with casts of the lumen which led to the cirri radiating toward its center. The central lumen must have been small with a restricted opening connecting it to the cirri. At least that is the best way I can explain why the lumen in the center wasn't cast the same way.

That explains the shape of the interstices, but not their number. I would expect greater number of cirri, structurally speaking, unless it is a transitional form of columnal, as either near the calyx or the holdfast. Are there any scientific papers that address crinoid anatomy in extreme detail? (Available with no fees; I'm on SS)

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#1 is likely the result of spalling due to freeze/thaw cycles. 

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Thank you everyone.  Now that I know what I am looking at, I am going to return to the same place to see what else I can find. 

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7 hours ago, Mark Kmiecik said:

I would expect greater number of cirri,

More than ten ?

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12 hours ago, Rockwood said:

More than ten ?

Enough to more completely fill the void. Only now I'm not sure we're talking about the same thing. I'm referring to the space within the columnal.

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57 minutes ago, Rockwood said:

Same orientation as the larger one.

3a.jpg.99b3d2fe3cf33b88ed5fd32cbba35dc8_LI.jpg

Ok. I got it. Thanks.

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