This is a crinoid stem, right?

[matgerke]

Found this in the scree of a road cut in what I think is the Ithaca Formation (early upper Devonian). It's a bunch of overlapping crinoid stems, right? There is a quarter sitting on top of the rock for scale.

Thanks in advance,

Matt

Edited August 20, 2016 by matgerke

[BobWill]

I believe that's correct. Nice plate. They look like impressions, right?

[matgerke]

Yes, impressions. I also found an adjacent plate with more crinoid impressions that I will glue to this one. I have half a mind to climb the cliff and see if I can't find the calyxes. If they are indeed crinoids.

Matt

Edited August 20, 2016 by matgerke

[caldigger]

Motorcycles were much smaller back then.

[BobWill]

Much smaller. If fact even the little crinoids kept tipping them over.

Good luck with the calyxes Matt. Down here to make a proper display we have to screen sample dirt to find enough broken pieces of crowns to glue together.

I read that a researcher estimated you have to encounter 100,000,000 dissembled pieces for every articulated crinoid you find. Places like Crawfordsville must make up for some really bad numbers other places.

[Herb]

nice stems

[tmaier]

Well, I'm going to be contrary and say these are not crinoid impressions, and might be cruziana, a trace fossil.

Look closely at the impressions, and they don't seem to be hemispherical, they seem to have a flatness to them, not at all like a crinoid stem...

Also, the trackway seems to have been covered up a bit before it became turned to stone. This would be hard to explain if it was an impression...

[Auspex]

Well, I'm going to be contrary and say these are not crinoid impressions, and might be cruziana, a trace fossil....

The rock is a bit weathered, but I see the same thing.

[TqB]

I agree with tmaier and Auspex - something like Arthrophycus perhaps.

A previous thread:

http://www.thefossilforum.com/index.php?/topic/59958-please-help-identify/

Edited August 21, 2016 by TqB

[matgerke]

Thought I would post a couple of better photos, in case this helps resolve the question.

[matgerke]

[matgerke]

[westcoast]

Crinoid stem impressions. 

[matgerke]

Someone on Facebook suggested tentaculites.  Thoughts?

[erose]

50 minutes ago, matgerke said:

Someone on Facebook suggested tentaculites.  Thoughts?

Those taper and are different in that they taper. 

[Rockwood]

Crinoid 100%

[abyssunder]

2 hours ago, erose said:

Those taper and are different in that they taper. 

Agreed!
Tentaculites are conical in shape, so their imprints should have the same shape, not cylindrical like yours.

 

What is sure, there are tiny crinoid columnal imprints on the surface, like this one:

 

[matgerke]

Yes, it's true that there are tiny crinoids (and shells) in the matrix.  But my puzzlement is that they seem to be far less weathered than the long tracks that are supposedly crinoid stems.  If those are really crinoid stems, why would they have so much less detail than the other fossils in the matrix?  That's what makes me think they might be burrows.

[ynot]

The crinoid stems are not there in the long grooves it is the print of what was there.

[Rockwood]

10 hours ago, matgerke said:

Yes, it's true that there are tiny crinoids (and shells) in the matrix.  But my puzzlement is that they seem to be far less weathered than the long tracks that are supposedly crinoid stems.  If those are really crinoid stems, why would they have so much less detail than the other fossils in the matrix?  That's what makes me think they might be burrows.

Notice that where the small pieces are sharp the shapes in question are faint. They were simply deeper in the matrix when it began to weather. Their small size affords them a certain amount of protection from abrasive forces as well.

If you find evidence that the shapes conform to each other then I will reconsider.

[TqB]

With the new photos, I agree they're crinoid impressions.

[abyssunder]

2 hours ago, Rockwood said:

Notice that where the small pieces are sharp the shapes in question are faint. They were simply deeper in the matrix when it began to weather. Their small size affords them a certain amount of protection from abrasive forces as well.

If you find evidence that the shapes conform to each other then I will reconsider.

You are correct.

[doushantuo]

ABOUT 2.4 Mb:

Thomk18-Lethia.pdf