Stalked Echinoderm

[Rockwood]

Fossils like this are found in nodules of carbonate rock within the Forks formation here in Maine. This appears to be a small (1.5 cm) section of stem. 

What is the bell shaped structure surrounding it ? It seems to be segmented but of a different composition.

[ynot]

5 hours ago, Rockwood said:

nodules of carbonate rock

 

5 hours ago, Rockwood said:

What is the bell shaped structure surrounding it ?

I think You first statement answered the question.

A calcite rich nodule or concretion.

 

Tony

 

Edit- Whoops, I missed the point. If You were talking about the small thing at the end of the segmented area- it may be a cephalon and the whole object is a trilobite.

Edited November 9, 2016 by ynot
Time to think!

[Rockwood]

Nodule may not be the best term. Here is another example of what I'm referring to. 

This might be a clearer shot of it. I've outlined the bell shape in blue. The segmentation is actually suggested more in what I would call a shadow of concretion above it. I've highlighted them in yellow. 

[ynot]

15 minutes ago, Rockwood said:

I've outlined the bell shape in blue. The segmentation is actually suggested more in what I would call a shadow of concretion above it. I've highlighted them in yellow. 

I see nothing highlighted?

Tony

[Coco]

Rockwood, je peux voir un peu vos lignes. Would vous les faites en rouge pour les rendre plus visibles s'il vous plaît?

 

noix de coco

[Rockwood]

Something tells me this is probably green. (Color blocks are useless to me ), but it should be more visible. 

[crinoid1]

Finally! Some crinoids in the ID section! What you are looking at is a river-tumbled piece of crinoidial limestone.

 

Check this link out: https://www.google.com/search?q=polished+crinoidal+limestone&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjEjobAq6rQAhUC7CYKHeIGC7oQ_AUICSgC&biw=1366&bih=603#imgrc=uMmCHTnxwvjA3M%3A

 

It's a piece of crinoidial limestone that's been machine-polished. I find it fun to see all the different shapes the stems can make when seen at different angles, and I am quite sure many of the mysterious objects visible on your rock can also be found in pieces of polished crinoidial limestone.

[Rockwood]

The first machine involved was likely a star point drill and sledge hammer. The next a steam shovel two turns of the century ago when it tumbled to the base of a railroad cut. Now the waves and ice polish it on the shore of Moosehead Lake. Many of these pockets are void now since around here limestone is one of the least durable rocks.

The highlighted shape, partially weathered and partially not, surrounding the stem section is ? 

[abyssunder]

I agree. That is a crinoid column in longitudinal differential polishing. The right side is less weathered (polished) than the adjacent left part, but the latter is not so profound polished to reveal the lumen; in other words, it is weathered to a level between the lumen and the external surface of the columnals, also the zig-zag sutures between them are visible. That's how I see it.

 

[Rockwood]

I agree. That's how I see it, but it's not the question!

[abyssunder]

In my thought, the bell shaped structure surrounding the crinoid column looks to be part of the crust covering the support matrix which is recrystallized probably, revealing the weathered crystalline structure with veins. Either has the same composition as the inner matrix, but is more weathered than that and colored differently, or a different mineral composition. I'm not seeing it to be a fossil, like a stromatoporoid, for example.

[Rockwood]

4 hours ago, abyssunder said:

In my thought, the bell shaped structure surrounding the crinoid column looks to be part of the crust covering the support matrix which is recrystallized probably, revealing the weathered crystalline structure with veins. Either has the same composition as the inner matrix, but is more weathered than that and colored differently, or a different mineral composition. I'm not seeing it to be a fossil, like a stromatoporoid, for example.

I was hoping for something more exotic, but honestly this is about what I expected. Can't really argue against it.

Thank you

[crinoid1]

Goodness! I am sorry! I totally missed the point of your question. Abyssunder has got it. I jumped right in before reading. I will be paying more attention now!

 

 

[Rockwood]

12 minutes ago, crinoid1 said:

Goodness! I am sorry! I totally missed the point of your question. Abyssunder has got it. I jumped right in before reading. I will be paying more attention now!

 

 

No need to be sorry. I do that all the time.

A good part of what I say is to give people a chance to correct me. More socially conscious folks probably see doing that as rude. My effective thus is likely seen as rude to some.