Fossil id

[Tomg]

Hi.

I found this fossil on the Lake Michigan shore in rocks that were brought in for a seawall, so I don't know where it might actually be from. Any help is appreciated.

 

Thanks

 

 

[Innocentx]

It would be nice to know it's size.

There may be a five sided thing going on here which could make it echinoderm of some kind, probably crinoid. A photo taken head on perpendicular to fossil might help clear this up.

[Tomg]

Thanks. Indeed size would help! I've included a photo with a ruler along side for reference.  Thanks.

 

 

[KimTexan]

This is a pretty uninformed guess, but I think it looks like a top down view of a stromatolite colony. Wait for others to weigh in though.

[Innocentx]

That's pretty big for a crinoid stem segment and I'm not seeing any of the other markers that would make it so.

Seriously I'm stumped. Hopefully someone will come along and recognize this.

[Bullsnake]

41 minutes ago, Innocentx said:

That's pretty big for a crinoid stem segment and I'm not seeing any of the other markers that would make it so.

Seriously I'm stumped. Hopefully someone will come along and recognize this.

 

Agreed...nothing screaming crinoid. Very interesting. Provenance could help in this case for sure!

[Tomg]

Here's another view of the sample, from the side showing the profile.

[ynot]

Looks like a weathered chert nodule to Me.

[KimTexan]

This is a pic of stromatolites from just googling the term. This is what it looks like to me. I have found what I believed were chert stromatolites before.

[Bullsnake]

I was thinking you're onto something, and now that's convincing. But I'm totally unfamiliar with stromatolites.

[ynot]

55 minutes ago, KimTexan said:

This is a pic of stromatolites from just googling the term. This is what it looks like to me. I have found what I believed were chert stromatolites before.

It is a good possibility. The singularity of the op"s piece is the only thing that confuses Me, because I thought strom were sorta (if the conditions are right for one then there are a whole bunch) groupings.

 

I am not well versed with stromatolites either.

[MRfossilMISTER]

at first i kinda looked like a little ammonite to me but it does kinda look stromato to me now that you mention it. im no good with stromatolites either, hope someone can solve this.

[Innocentx]

With this last picture I'm back to crinoid again. This object is very worn but I think I see a plate from the aboral cup(calyx).

[KimTexan]

I’m not seeing crinoid there. Crinoids have 5 thin pentagonal shaped plates that form part of the crinoid cup or calyx with another set of 5 plates and sometimes another set of 5. I still don’t see that here.

See images below.

Pic taken from:

http://www.catnapin.com/Fossil/Echinoidermata/ffCrinoids.htm

pic taken from here

 

[Wightlight]

Might be a reach but it looks a little bit like the heavily eroded sea urchins we find here in Denmark

Edited August 6, 2018 by Wightlight

[Innocentx]

I think @Wightlight may have something. I will agree with him! Worn echinoderm(urchin).

[abyssunder]

I don't want to discourage anyone, but couldn't it be just a concretion with onion skin weathering?

[ynot]

12 minutes ago, abyssunder said:

I don't want to discourage anyone, but couldn't it be just a concretion with onion skin weathering?

That is what I thought on this.

[KimTexan]

It could be a concretion, but I’m still thinking stromatolite colony. I guess they could be a type of sponge too.

These don’t look like the OP item exactly, but you get the idea.

Here are 2 pics from another post. The idea the first was a stromatolite was debated, but in the end it was determined to be a stromatolite from Morocco. 

 

This is from the same discussion and they are from Wisconsin found by a TFF member.

 

I can definitely be wrong.

I’ll have to pull up some pics of ones I found that I believe are stromatolite. I’ll do that later though.

[sixgill pete]

Knowing where the rock for the seawall came from is the key. It would rule out some things and rule in others depending upon the geologic age. Otherwise all guesses are purely speculation, not identification.

[Fossildude19]

22 hours ago, KimTexan said:

This is a pic of stromatolites from just googling the term. This is what it looks like to me. I have found what I believed were chert stromatolites before.

 

Kim,

These actually look more like beekite rings, than stromatolites, to me.   

Where is this photo from?

 

The one thing I don't see here in the item posted for ID, is the layering that is evident in all Stromatolites.  

 

I would discount  echinoids based on the area - Not many echinoids around in the Ordovician/Devonian/Silurian, which makes up a large portion of the geologic makeup of the area.

 

I honestly think that @Innocentx may be correct with the crinoid calyx idea - if it was in a seawall, it could have been highly eroded by the water action, or this could be a steinkern of a crinoid cup. The other option, would be a solitary beekite ring. 

 

Just my two cents.  

 

 

[abyssunder]

Just found, what to me, has the best resemblance (all characters) with the specimen in question.

 

comparative picture from here

 

[ynot]

14 minutes ago, abyssunder said:

Just found, what to me, has the best resemblance (all characters) with the specimen in question.

OK, but what is it?

[GeschWhat]

1 minute ago, ynot said:

OK, but what is it?

Pisolites

[KimTexan]

 

@Fossildude19 like I said, I just googled the term and it came up in the group of images. Poor choice. I went back and looked to see where it came from. It originated in Pinterest which isn’t a reliable resource.

 

Yes, it does look like beekite rings now that you mention it.

 

It seems apparent that whatever it may be it is highly eroded.

This is another pic of a stromatolite from Wisconsin. It may not look exactly like the OP item, but it does have some of the same qualities. This pic is from a reliable source.

https://wgnhs.uwex.edu/wisconsin-geology/fossils-of-wisconsin/stromatolite-gallery/

It is the Wisconsin Geologic and Natural History Survey.

 

These are stromatolite colonies from the Ordovician of Northwest Arkansas that I came across while fossil hunting. They are a some form of chalcedony. Looks a lot like flint. Here is one eroded colony. My toes for size comparison. Sorry best I could do in the field.

 

Another colony

 

One broken open. You can see a little of the layering, but it is more prominent than what is evidenced in the pic. Subsequent to me finding them and identifying them as stromatolites I found pics of colonies just like these in an Arkansas geological group weekly blog identifying them as stromatolite colonies.

 

 

I would like to see a pic of the whole rock the item is on. In the 2nd pic of the OP it almost looks like there is additional layering on the surrounding rock. The targeted item could be part of a larger item we are not seeing. 

@Tomg  May we have another pic of the whole rock the item is on?

 

@abyssunder how big do pisolites get.

How often do you find a solitary pisolite?