What is surrounding this Crinoid stem?

[solidus]

Found this on the beach today... At first I thought it was a screw. Seems to be the stem of a Crinoid, but totally surrounded by this white, chalky, calcium like substance. What exactly is going on here?

 

Also, I live on Long Island NY which I know is not home to any native fossils due to its geology, so are most limestone fossils like this basically washed here from other locations?

Edited August 29, 2023 by solidus

[DPS Ammonite]

I think that the white chalky areas are the calcite crinoid stem that is dissolving away. The black inner part is the filling, an internal mold.

[Ludwigia]

This appears to me to be something man-made which has spent a lot of time being eroded, but I may be wrong.

[TqB]

The white is probably the actual calcite crinoid stem material, the black part being the matrix filled hollow lumen. There are some other smaller white bits in the rock that look like crinoid fragments.  

[solidus]

2 minutes ago, Ludwigia said:

This appears to me to be something man-made which has spent a lot of time being eroded.

Are you saying you do not think its a Crinoid fossil at all, but a screw or something? Would that even make sense?

[DPS Ammonite]

3 minutes ago, solidus said:

Are you saying you do not think its a Crinoid fossil at all, but a screw or something? Would that even make sense?

Here are some observations that might help determine if it is a screw or crinoid. Does the white area fizz in acid? Is the inner black part a metal and is malleable when poked with a hard metal pin? Is there pitch of the possible threads visible in a microscopic shot?

[solidus]

Adding a dry shot where you can see some of the surrounding impressions better.

 

 

[DPS Ammonite]

Clearly a fossil. The only screw that you might find in an Archimedes.

 

https://en.m.wikipedia.org/wiki/Archimedes_(bryozoan)

[Randyw]

16 minutes ago, Ludwigia said:

This appears to me to be something man-made which has spent a lot of time being eroded, but I may be wrong.

I’m with ludwigia. It’s a bolt in concrete that was drilled into a fossil bearing rock. If you blow up the picture you can see the inclined thread pattern……

Edited August 29, 2023 by Randyw

[solidus]

6 hours ago, Randyw said:

I’m with ludwigia. It’s a bolt in concrete that was drilled into a fossil bearing rock. If you blow up the picture you can see the inclined thread pattern……

 

Would the bolt attract a magnet? I tried and got no magnetism at all. I guess it could be aluminum? It seems to be the exact same material as the rock itself... there is really no indication that its metal at all. I am really very new to all this... so I have absolutely no idea. The surrounding impressions that seem to be other parts of Crinoids/Bryozoan led me to believe it would make sense for a stem to be here. How would a piece of metal even end up like this? Would it not just erode and rust away? I am VERY confused

[DPS Ammonite]

6 hours ago, Randyw said:

I’m with ludwigia. It’s a bolt in concrete that was drilled into a fossil bearing rock. If you blow up the picture you can see the inclined thread pattern……

 

Interesting idea. Weirder things have happened. I guess we need to see if the black center is metal or not.

[solidus]

Some more photos for you sleuths. There is another much tinier version of the same screw-like object on the other side of the rock. Another screw but smaller? Seems odd...

 

Also that white substance is in other spots in small amounts here and there...

 

 

Edited August 29, 2023 by solidus

[Fossildude19]

It's a crinoid stem. I'm fairly certain.

[TqB]

Definitely crinoids, and with a very good internal mould showing the lumen (some would say cast but that discussion has been had before a few times ). Also impressions of bits of shell, presumably brachiopod.

Edited August 29, 2023 by TqB

[solidus]

46 minutes ago, TqB said:

Definitely crinoids, and with a very good internal mould showing the lumen (some would say cast but that discussion has been had before a few times ). Also impressions of bits of shell, presumably brachiopod.

So let me try to visualize whats going on here. Is the actual screw-like part just limestone that replaced a cavity that was INSIDE of the Crinoids stem itself? And the white part on the outside replaced the actual organic material of the Crinoid? So is the screw part essentially like what you would get if you filled a cast mould with plaster, and the white part is the mould? Is the stem actually like a hollow screw-like tube when it was alive? In that case the white portion is the actual animal and the dark screw portion is just its hollow inside?

 

Sorry for so many questions... just trying to wrap my head around it.

Edited August 29, 2023 by solidus

[minnbuckeye]

1 hour ago, solidus said:

 

 

Isn't the second fossil Archimedes????? If one enlarges his first newer image and look to the left and a bit lower than his "crinoid".

[Ludwigia]

I'm really stumped on this one since I'm trying to imagine a species of crinoid which would have such a screwy internal mold of the lumen.

 

I'm editing this a few minutes later since I just discovered something in my own collection which I was never really able to identify. I found a few pieces like this one  at a construction site in Caledon, Ontario, but was never able to find out where they originated. Bill Hessin suggested that it came from the Silurian Gasport/Amabel Formation at the quarry in Milton and a couple of crinoid specialists suggested such genera as Dimerocrinites or Siphonocrinus.

 

[Rockwood]

1 hour ago, solidus said:

So let me try to visualize whats going on here. Is the actual screw-like part just limestone that replaced a cavity that was INSIDE of the Crinoids stem itself? And the white part on the outside replaced the actual organic material of the Crinoid? So is the screw part essentially like what you would get if you filled a cast mould with plaster, and the white part is the mould? Is the stem actually like a hollow screw-like tube when it was alive? In that case the white portion is the actual animal and the dark screw portion is just its hollow inside?

 

Sorry for so many questions... just trying to wrap my head around it.

The white part is the stem. The minerals have been rearranged some though. The dark part is the hole in the stem. The hole was fluid filled in life. 

[Rockwood]

1 hour ago, solidus said:

actual organic material of the Crinoid?

There was soft tissue covering the stem, but that is very rarely if ever preserved. Ligaments ran through it which last long enough that sections are preserved with the ossicles still articulated. 

[solidus]

54 minutes ago, Ludwigia said:

I'm really stumped on this one since I'm trying to imagine a species of crinoid which would have such a screwy internal mold of the lumen.

 

I'm editing this a few minutes later since I just discovered something in my own collection which I was never really able to identify. I found a few pieces like this one  at a construction site in Caledon, Ontario, but was never able to find out where they originated. Bill Hessin suggested that it came from the Silurian Gasport/Amabel Formation at the quarry in Milton and a couple of crinoid specialists suggested such genera as Dimerocrinites or Siphonocrinus.

 

I'm not sure how relevant this is since I am just getting into all of this, but I know that Long Island is pretty much entirely made up of glacial moraine from glaciers that came down from Canada during the Pleistocene Epoch. This is why we really have very few fossils at all since all of the exposed rock is relatively new. I guess it would make sense that whatever fossils are here came down from the north (Canada).

 

Although I could be very wrong...

 

Your fossil has pretty much the exact same tight thread pattern as mine... Almost like a machine screw.

Edited August 29, 2023 by solidus

[Stingray]

It’s an internal crinoid cast , mold, ETC. whatever term you like. Yes they often look like screws …. However who the heck would put a screw that size in a rock at a construction site. I’ve been on plenty and can’t think of a single reasonable explanation of putting that size screw into rock.   . What blasting with firecrackers. It’s a fossil with brachiopods also. Nice screw hole

 

oh and it’s not concrete so it’s not for stringers.

Edited August 30, 2023 by Stingray

[solidus]

47 minutes ago, Stingray said:

It’s an internal crinoid cast , mold, ETC. whatever term you like. Yes they often look like screws …. However who the heck would put a screw that size in a rock at a construction site. I’ve been on plenty and can’t think of a single reasonable explanation of putting that size screw into rock.   . What blasting with firecrackers. It’s a fossil with brachiopods also. Nice screw hole

 

oh and it’s not concrete so it’s not for stringers.

Yeah honestly at first I wasnt sure... But then a few folks here had me thinking it really could be a bolt. Now it seems pretty clear that is not the case.

 

I assume the white part is just calcite right? My research tells me that its often found as part of limestone from the presence of marine shells.

[EMP]

Tapping into my engineering background to say this probably isn't a bolt, or screw. Why anyone would go through the effort of drilling a bolt into a rock of that size is beyond me, unless it got blasted/chipped away at some point, but even then I have my doubts, since you usually wouldn't fill the bolt hole with concrete afterwards (it would also be a tiny bolt, so I'm not sure what purpose it would serve at a construction site. There's no way it could be part of a tie back or something geotech related at that size). I'm also not seeing any aggregate in the white material, which makes me lean away from it, too. Also, most bolts would be magnetic. 

 

I'll throw my hat into the crinoid ring, and say the white stuff is some kind of mineralization associated with the fossil. Maybe calcite or some other carbonate. There's a site in Georgia where you would find trilobite molds/casts with mineral halos around them, so there's definitely precedent for that kind of preservation of Paleozoic inverts. 

 

Any rate, cool find, especially for Long Island! My understanding is fossils are pretty hard to find there. 

[Stingray]

1 hour ago, solidus said:

I assume the white part is just calcite right? My research tells me that its often found as part of limestone from the presence of marine shells.

Yes it was probably a hot intrusion of acidic fluid , replaced the shell with some type of quartzite. 

[solidus]

1 hour ago, EMP said:

Tapping into my engineering background to say this probably isn't a bolt, or screw. Why anyone would go through the effort of drilling a bolt into a rock of that size is beyond me, unless it got blasted/chipped away at some point, but even then I have my doubts, since you usually wouldn't fill the bolt hole with concrete afterwards (it would also be a tiny bolt, so I'm not sure what purpose it would serve at a construction site. There's no way it could be part of a tie back or something geotech related at that size). I'm also not seeing any aggregate in the white material, which makes me lean away from it, too. Also, most bolts would be magnetic. 

 

I'll throw my hat into the crinoid ring, and say the white stuff is some kind of mineralization associated with the fossil. Maybe calcite or some other carbonate. There's a site in Georgia where you would find trilobite molds/casts with mineral halos around them, so there's definitely precedent for that kind of preservation of Paleozoic inverts. 

 

Any rate, cool find, especially for Long Island! My understanding is fossils are pretty hard to find there. 

Thanks for the insight! Yes I also am under the impression that they are quite rare due to all of the land being the result of geologically recent glaciers. This is the 2nd Crinoid I found on this beach actually (the first was last week and is what actually got me into this whole fossil hunting mess ) The beach is pretty much entirely shells and smooth stones, but scattered about are these limestone fragments that are 2-3x larger than the surrounding stones. They are very easy to spot and actually pretty common. I have taken 2 trips and came home with something each time. I have noticed that almost every piece of limestone has at least some tiny impression of a fossil on it... but most are too faint to care much about. This one obviously stood out to me today...

 

Im hoping to find some more cool stuff... although I have no idea where these would have came from geologically.. I assume washed here by currents,