First (TFF) Post Ever! Help a Rock Noob ID this mystery fossil!

[Rock Noob]

Hello, folks!

 

I'm one of those guys that finds fossils fascinating, and loves the natural history museums, but has never really tried to find fossils.  I bought a one-inch fish fossil in a museum gift shop many years ago, for a few bucks, and for along time, that comprised my fossil collection.  One day, my collection grew 100% when I realized one of the random rocks bordering a garden at the house I was renting had a pretty large fossil apparent in it.

 

I took that stone, and have had it on my mantle for years.  I always wondered what it was, and finally I stumbled on this site and decided to see if the good folks here can help me settle once and for all what it is.  I have a good guess, but we'll get to that.  I read some ID threads and the posting guidelines, and I realize that I've already made one mistake, in not including a scale inthe pictures.  Oh well, hopefully my descriptions of size will suffice.  Also, my cheap little camera struggles with focus and lighting on macro pics, and I'm no photographer.  But it's a pretty large fossil so hopefully you can see what it is.

 

I'd be super stoked to have my suspicions confirmed, or destroyed, either way, as long as I find out what it is and can match it to a picture of something pretty similar.  Speaking of that, I have looked at fossil ID charts and at pics, and while I can't find anything that matches it exactly, I feel like I'm close.

 

In any case, here are the pics and then I'll say what I think it is so you can all laugh at the guesses of a Rock Noob.   As mentioned before, it was found in a backyard in Oklahoma City, but I suspect it was not native, and was carried there somehow.  It does resemble rocks I've seen near just about every beach I've ever been to, especially on the Gulf of Mexico.  I'm thinking it's just some sort of sedimentary limestone.

 

The fossil itself is about one inch across the round cross section you can see at the left end.  It appears to be the broken end of a long, cone shaped "shell" of some sort.  The shell continues into the rock for about 4 inches, and I can't see that it comes out the other side, but I get the impression it was longer at some point.  My observation of the segments that make up the object, and the suggestion of a spiral-chambered structure I can sort of see inside the broken end, lead me to believe it was some sort of straight-cone-shelled ammonoid creature.

 

My feeble web research indicates that there were such creatures, many types, in fact.  I've found many drawings and pics that are close, but not dead-on enough for me to close the case.  My official guess is that my fossil came from something approximately like this:

 

But, hey, I'm no expert on ammonoid or nautiloid taxonomy, so I leave it to you, good experts!

 

The Photographs: (poor as they are)

 

Main view, you can see into this broken end and in person, sort of see how it looks as if it had spiral chambers inside.  The pronounced longitudinal ridges or scores are very evident.  There is a slight curve to the fossil but it is broken in some places and I think it was originally fairly straight.  It has a regular gentle taper towards the end that disappears into the rock.  What I believe were originally open spaces in the "shell" have filled with some sort of crystal that grew there.

 

Another view of this end.  The whole rock is about 8 inches in length, perhaps 5 inches fron to back, a few inches thick.  The fossil is clearly separated from the rock, it looks like I could tap the rock with a hammer and the fossil would just fall out.  I don't plan to try that, however.

 

You can see there is a hole or crack about one inch from the leftmost extremity.  You can see inside and see the crystalization that has taken place in there.  More importantly, toward the upper left of that crack, you can see that the outer surface of the object has broken away.  This reveals that each of those "cells" apparent on the outside are hollow inside- the object is in fact a stack or a spiral arrangement of many, many, little chambers.  You can see more open cells on the center-right area as well, and these have filled in.  This strongly suggests an ammonoid or nautiloid mollusc to me.   It appears that the transverse chevrons, along with the longitudinal scores are actually the divisions between tighly packed shell chambers or sections.  The chevrons divisions appear in annular rings or a spiral around the object, at regular intervals all along it's length, on every part I can see.  These scores and chevrons look very much like the sutures evident in other shells, but I have yet to find a picture that matches closely.

 

 

Moving to the right, this chip came off without effort, basically just fell off (long ago.)  you can see the imprint of the object, along with a very clear imprint of some scallop-like bivavle mollusc.  I'm already convinced it's a sea creature, but this bivalve further indicates where this came from.  My object disappears into the rock behind that bivalve imprint.  I feel I could dig more of it out, but I would rather leave the rock as-is.

 

Closer shot of that area.  The shell itself is gone but it left a perfect, detailed imprint of the little scallop.  Numerous other small shells are evident, as with all this type of rock.

 

From reading the ID advice I realize that a "hand shot" isn't the best indicator of size, but I promise, to the best of my knowledge, that my hand size is as average as it comes.

 

There are other things hiding in here, it hard to see but this area seems to have something going on underneath it.  

 

Hopefully htis is enough for someone to recognize my mystery "shell."  I won't be surprised if some one can say that "this is a very common ________ from ________ where they dig them out by the ton in ________limestone quarry."

 

But you never know, this might end up being the find of the century! (I won't hold my breath. . .)

 

Thanks for looking!

 

 

I also have two rock samples, one of which may be petrified wood.  Is there a similar "Rock ID thread" I can post them in?

 

-Brian

 

 

 

 

 

 

 

 

[ynot]

Welcome to TFF!

I think Your fossil is a rudist, a type of bivalve.

You can post Your wood here in this sub forum, but it is best to start a new thread for it.

[Fossildude19]

What state/county was this found in?

 

Oh,.. and Welcome, to the Forum.  

[Al Dente]

I think you have a solitary rugosan which is a type of Paleozoic coral. What you see is actually a steinkern of the coral (the mud that filled the coral and the coral itself has dissolved away).

[ynot]

Hey @Rock Noob

Can You provide close up pictures of the exposed end of the fossil? (Same as first 2 pictures just closer and more detailed.)

 

To Me it looks like a thick shell layer with a lighter sediment fill, but Al Dente maybe correct.

[Rock Noob]

1 hour ago, ynot said:

Welcome to TFF!

I think Your fossil is a rudist, a type of bivalve.

You can post Your wood here in this sub forum, but it is best to start a new thread for it.

Thanks for the welcome, I appreciate it!

 

I did start a new topic for my "wood" piece.

 

 

[Rock Noob]

1 hour ago, Fossildude19 said:

What state/county was this found in?

 

Oh,.. and Welcome, to the Forum.  

Hi, thanks for the welcome!

 

It was found on Cherry Street in Oklahoma City, OK, near Will Rogers World airport.  I couldn't easily find a way to make google tell me the county.  However, this rock was in a garden border made from widely disparate rocks, that even to my untrained eye were obviously a collected mixture from various sources.  I am not sure, or even unsure, that this rock is native to the area.  It looks like many sandstone/limestone type rocks I've seen anywhere that used to be seafloor, which is nearly all of NA.

 

I'm sorry I don't have more detailed or verifiable location info. 

[Rock Noob]

1 hour ago, Al Dente said:

I think you have a solitary rugosan which is a type of Paleozoic coral. What you see is actually a steinkern of the coral (the mud that filled the coral and the coral itself has dissolved away).

I could easily see it being coral- the fact that it seems to be a collection of little cells would suport that.

 

As much as I though about it being like a chambered shell, the outer structure of it is way more complicated than most shells, and it isn't all one piece.

 

I will look for some pics of that coral you mentioned.

 

Thanks!

[Rock Noob]

36 minutes ago, ynot said:

Hey @Rock Noob

Can You provide close up pictures of the exposed end of the fossil? (Same as first 2 pictures just closer and more detailed.)

 

To Me it looks like a thick shell layer with a lighter sediment fill, but Al Dente maybe correct.

I will try.  My camera is pretty limited, but I will make the attempt.  It is clearly a tubular shell of some sort, be it the body of a coral colony or whatever.

 

Give me about 4 hours and I can get home to take more pics. 

[Fossildude19]

Oklahoma City is in Oklahoma County, which, according to this geologic map is surrounded by Permian and Quarternary aged rock.

This looks more like Permian material, to me, ... so a Rugose coral would be a fair guess. 

That would also mean that your shell is actually a brachiopod, possibly some species of Spiriferida . 

 

 

[Rock Noob]

3 hours ago, Fossildude19 said:

Oklahoma City is in Oklahoma County, which, according to this geologic map is surrounded by Permian and Quarternary aged rock.

This looks more like Permian material, to me, ... so a Rugose coral would be a fair guess. 

That would also mean that your shell is actually a brachiopod, possibly some species of Spiriferida . 

 

 

Very informative, thanks.  

 

I looked at those brachiopods and I agree, they look spot-on to what I have there in my rock.  Details match pretty close.

 

I'm pretty convinced it's coral by now, but the few rugose corals I've seen illustrated are much more wrinkled (which I just learned is the meaning of 'rugose') than this is. However, like fish, dogs, and ornamental plants- there can be quite a bit of variation, even within species.  

 

Check my next post for many more pics, and thank you for the input!

 

 

[Rock Noob]

OK folks, you've offered such an impressive response that I had to come through with better pics.  The ones from this morning were and afterthought and hastily taken as I grew late for work.

 

We have about reached the limit of my little Sony pocket cam.  These pics are taken with the lens about 1" from the rock and it's really having issues focusing, although good light and turning the flash off helped.

 

Hopefully these offer better light and angles.  First, here are some scale pics.

 

I read that coins weren't universally known, different continents and all, but I bet beer caps and bic lighters exist in ready supply on all 7 contininents. . .

 

Another view

 

End view

 

More end views into the broken end.  I can clearly see that it's a convolute shell that makes a tube, but I can't determine the structure of what was inside.  I'm not sure if that stuff inside was part of the organism or what, but my gut feeling is that the tube wasn't open, but was rather a stack of chambers all the way up, that filled in with some sort of crystal growth.  The crystalline material looks like shiny sand glued together.

 

Rotating around some, you can really see the complexity of the surface structure.

 

Rotating more, I wish I coud get sharper focus, but you can still see the deep channels and chevron-shaped fissures that divide the "cells" of the outer surface.  You can also see broken open "cells" that reveal the hollow chambers within.  On the left, you can see from the broken edges that the interior stuff looks like thin membranes that grew a sheet of crystals on each side.  It's amazing, these must have existed as pockets of open space for eons, crystals slowly forming inside like a geode. . .

 

Now for side views.  Sorry for the focus but you can see into those broken "cells."  It's really sort of like an ear of corn, with tightly packed, oddly shaped kernels that are hollow if you shave off their tops.

 

Side view.  It's kind of crazy how distinct it is from the matrix.  You can actually see space betwen the materials.  I'm sure it would be easy to free the rest of the fossil.  

 

Using an LED light to illuminate the interior.  Doesn't show much but for what it's worth, it supports the idea that this was a column of flat chambers.

 

Moving to the right, these chambers lost their tops too, but they filled in with some mineral material that seems different form the crystal.

 

Farther right, the brachiopod becomes visible at the right.  Also, the part of the tube under the chip that came off has fewer of those transverse chevron divisions, so maybe those are an effect of exposure or something.  Or maybe the creature was just different near this end.

 

Another shot.  I can't tell if it just ends here or disappears into the rock.

 

The brachiopod with its imprint.  This part is weird, possibly not a fossil at all, since there is no "object."  The shell of the brachiopod is totally gone, and only the "mold" that formed around it remains.  The shell itself dissolved or whatever, but didn't fill in with anything like the other thing did, the  steinkern  as I have been told it is called.

 

Brachiopod again.  Amazing what detail was captured in the impression, this could only have happened if the interior item simply dissolved away as it must have.  You can also see a neat "V" shaped thingy to the right of the brachiopod, as well as many other tiny fossils. 

 

Vertical view.  If you look at the missing parts it seems like the edges folow the transverse chevrons, supporting my belief that they are a feature of the organism, and represent the divisions between discrete parts of the overall structure.  Or they could just be cracks.

 

Bonus pics- A better pic of that area on the rear that is clearly something influencing the rock.

 

A place where you can clearly see a bivalve shell in profile.

 

Some sort of shell section is evident onthe surface here.

 

Thanks for looking, I appreciate everyone's input and look forward to learning more about what I've got here. 

 

 

 

 

 

 

 

 

 

 

[ynot]

@Al Dente, sorry but I see nothing to make Me think this could be a coral.

Maybe @JohnJ or @Uncle Siphuncle can help.

Tony

[Ludwigia]

13 hours ago, Al Dente said:

What you see is actually a steinkern of the coral (the mud that filled the coral and the coral itself has dissolved away).

 

That would make it a mold, right?...or is that a cast?

[TqB]

It looks like a caniniid rugose coral, partially a mould/steinkern with the external calcite epitheca and septa just inside having been dissolved.

The deeper internal structure seems to have been previously thickened by silica which is a common occurrence. So the hollow chambers are original, with what looks like a quartz crystal lining around each one.

 

Caniniids have the large, horizontal tabulae that are reminiscent of cephalopod septa. They are mainly Carboniferous but there are some Permian ones.

 

The chevrons in Rock Noob's specimen are folded tabulae edges (the folds being vertically discontinuous septa of the form known as amplexoid). 

Seen nicely here, for example:

 

 

Here's a singlel tabula from a Carboniferous specimen. It's actually the under surface but you can see the folds that project as septa on the upper surface.

 

 

And this vertical section shows the tabulae and chambers between them.

 

 

 

 

 

[ynot]

OK, I will concede t-- this is a rugose coral.

 

Tony

[Rock Noob]

6 hours ago, TqB said:

It looks like a caniniid rugose coral, partially a mould/steinkern with the external calcite epitheca and septa just inside having been dissolved.

The deeper internal structure may previously have been at least partly replaced or covered by silica which is a common occurrence..

 

Caniniids have the large, horizontal tabulae that are reminiscent of cephalopod septa. They are mainly Carboniferous but there are some Permian ones.

 

The chevrons in Rock Noob's specimen are folded tabulae edges (these being vertically discontinuous septa of the form known as amplexoid). 

Seen nicely here, for example:

 

 

Here's a singlel tabula from a Carboniferous specimen. It's actually the under surface but you can see the folds that project as septa on the upper surface.

 

 

And this vertical section shows the tabulae and chambers between them.

 

 

 

 

 

TqB, 

 

Thanks for your informative and undoubtedly correct information.

 

Other pictures of Rugose coral didn't quite have me convinced, but this is clearly what I have, or very close.  I especially appreciate the way you explain that this sample does indeed have structure suggestive of cephalopods, that makes me feel better.  During my initial ruminations, I thought this piece might have been a "tube worm" of some type, but the complicated structure of the "tube" made me think it was more developed structure, like a shell.

 

I realize corals aren't "tube worms" but they are an animal that lives in a tube-like structure!  Heh heh, can't really take any credit, there.

 

In any case, I found a number of other descriptions of coral anatomy and pictures, and I've been studying all morning instead of umm, working. . .

 

While I am sure that the info I am getting here is good, I still coudn't find a pic that really matches what I have.   However, I did find this:

This picture is much better than mine.  This photo has a scale, and even includes a reverse "C-hair" for extra size comparison. . .  This is a sort of "missing link" for me along with learning about the concept of a steinkern.  In this example, on the left, we see the flared shape and outer surface that is typical of the pictures and drawings I can find of rugose corals.  The revelation for me is on the right, where you can see "cells" very much like on my sample, and even see that the cells are filled in with something, like some of the cells on my specimen.  Clearly the same thing.

 

So, this leaves me with why mine doesn't look like all the others I can see that are more whole-  Let me lay this out so I can see if I have this correct:

 

-The coral was buried in ocean sediment

-The animal flesh inside rotted away virtually instantly by geologic time scales, leaving some hollow or sediment filled spaces inside, that crystalline silica eventually began to form in.

-This  sediment material formed a concretion (is that right?) around the calcium-based parts of the coral skeleton, while the skeleton still existed, forming a relatively hard and detailed "mold" of both the outside and at least to some extent, the inside of the "tube."  The scores and chevron-crack features evident on my specimen are actually the reverse of the inside of the skeleton's outer layer.

-The skeleton dissolved, but was not replaced by mineral as sometimes happens with say, large dinosaur bones or the last example from Tarquin.  Whether or not the skeleton gets mineralized or just dissolves is a factor of the situation and the available minerals.

-This is why: 

A- the outside looks different- mine is really a "cast" of the inside of the skeleton, or in other words, a steinkern.  The skeleton itself is gone and wasn't replaced, at least the outer surface wasn't.

B- the specimen appears to be separate from the rock, and has such a neat dividing line between steinkern and matrix, is because that space is where the thin skeleton surface layer used to be, and when it dissolved it left a thin, empty space between the steinkern and the outer "mold" of matrix.

 

Is that an accurate description of the origin of this thing?  If that's right, then I guess this mystery is solved. . .

 

Wow, thanks folks!  I appreciate your time and information.  Ultimately, my initial guess wasn't correct, but what fun it was to find the right one. . .

 

I might have to try to dig some of my own fossils, yet.

 

Could fossils perhaps be found, near Olathe, KS?

 

[ynot]

Your dissertation is correct as far as I can see. I will add that the coral polyp only occupies one chamber at a time, the living chamber.

 

[Fossildude19]

20 minutes ago, Rock Noob said:

I might have to try to dig some of my own fossils, yet.

 

Could fossils perhaps be found, near Olathe, KS?

 

 

 

You could start your research HERE. 

Supposedly, there are fossils to be found in Johnson County. 

 

Keep in mind, the information on the site is very old, and may no longer be accurate or pertinent. 

Happy Hunting. 
Regards,

[BobWill]

Your annylisis is very thorough and informative. I will add something about casts and molds that seems to confuse a lot of amateurs and has led to some vigorus and unresolved discussion on the forum.

 

If you use the terms alone they can have different meanings like a lot of words in english, but if you add the words “interanl” or “exteranl” before “cast” or “mold” they have more specific meanings that may seem counterintuitive. I don't believe you did add the other terms but if you see them in other posts this may help explain why and why it may be more clear to use the words the way other proffesionals would.

 

You correctly called the external surface on the matrix a mold but your steinkern is actually an internal mold. In paleontology the terms are used the same as in sclupture. A cast is a copy of the original and a mold can form a cast. If you are talking about the inner surface of a structure then the original material doesn't suddenly become a mold and what it forms become a cast. A steinkern is a mold capable of forming a copy, or cast of the original material's inner surface. That cast would generally be concave so the internal mold like what you have is convex. I hope this helps and I hope it doesn't re-ignite this old discussion unless it gets resolved. The last time I don't believe we ever heard from an actual proffesional.

[Rock Noob]

1 hour ago, ynot said:

Your dissertation is correct as far as I can see. I will add that the coral polyp only occupies one chamber at a time, the living chamber.

 

Thank you for the confirmation.  I had also wondered about what part the coral actually occupied- this explains how the chambers appear sealed off- because they are! 

[Rock Noob]

1 hour ago, Fossildude19 said:

 

 

You could start your research HERE. 

Supposedly, there are fossils to be found in Johnson County. 

 

Keep in mind, the information on the site is very old, and may no longer be accurate or pertinent. 

Happy Hunting. 
Regards,

Wow, thanks, my house is within minutes of several of those sites.  I may have to go take a look.  Problem is, I won't really know what to look for, besides "order among the chaos" or things that are apparently sedimentary rock.   What do you do, pick up likely river rocks and smash/split them with rock hammer until you find something? 

 

As you can tell, I have a talent for preposterously ignorant simplification. . . 

 

And as old as that info may be, I'm pretty sure that the fossils are older, and possibly still there. . . J/K!

 

Seroiusly, thanks for your info, Sir.

[ynot]

Each site has its own collecting method, what works in one place may be useless in another site. 

When You get to an area do a surface search. look at the type of fossils and rock in the area. This should tell You if You should be splitting rock or screening or surface collecting or what ever.

If You are not sure You can always try different methods to see which will provide the best collecting.

 

Good luck!

Tony

[Rock Noob]

1 hour ago, BobWill said:

Your annylisis is very thorough and informative. I will add something about casts and molds that seems to confuse a lot of amateurs and has led to some vigorus and unresolved discussion on the forum.

 

If you use the terms alone they can have different meanings like a lot of words in english, but if you add the words “interanl” or “exteranl” before “cast” or “mold” they have more specific meanings that may seem counterintuitive. I don't believe you did add the other terms but if you see them in other posts this may help explain why and why it may be more clear to use the words the way other proffesionals would.

 

You correctly called the external surface on the matrix a mold but your steinkern is actually an internal mold. In paleontology the terms are used the same as in sclupture. A cast is a copy of the original and a mold can form a cast. If you are talking about the inner surface of a structure then the original material doesn't suddenly become a mold and what it forms become a cast. A steinkern is a mold capable of forming a copy, or cast of the original material's inner surface. That cast would generally be concave so the internal mold like what you have is convex. I hope this helps and I hope it doesn't re-ignite this old discussion unless it gets resolved. The last time I don't believe we ever heard from an actual proffesional.

Hey, thanks for your kind response, and your confirmation of my various hypotheses.

 

I'm amused by the rest, because from Ludwigia's post above and from your own, it is clear that there has been some spirited debate over the various particulars of the definitions of certain words!

 

Well, as the Rock Noob, far be it from me to presume to argue with anyone here, but I will clarify my understanding of those terms and how I meant them.  My background with molds comes from my undergraduate sculpture degree and the fact my job IRL involves teaching people aerospace composite fabrication.  Forgive me for the off-topic aside, but it relates to our discussion.

 

The way I would relate the terms, and you guys can make of it what you will, this is merely my opinion, is this:

 

The original skeleton that we started with could be called an internal mold, in that an impression was made from it, therfore it was a mold, by definition.  (in the industry we might also refer to this as a "form" or very commonly, a "plug" and in the case of 787 fuselage tubes, a "mandrel" but it all means the same as "internal mold")  This impression can also be a mold, the one we will now refer to as the external mold once it is made by the concretion, and at this point, if you turn around and cast something from that external mold, you'd have a cast of that mold that matched the original item, at least on the exterior.

 

But in this case we have a "tube" so there can be an interior impression or mold made as well- the steinkern.  But it goes both ways- the steinkern was itself a cast of the mold that was constituted by the original skeleton.  So it is at that time a casting, but then later it could also have been a mold- except in this case it never was, as no mineral filled in the space once the skeleton dissolved, apparently.

 

I'm not arguing at all, I'm sure you are correct in how I should use the terminology, I just wanted to explain my reasoning. In any case, this has all been vastly informative and I'm very glad I finally found this resource.

 

I'm looking forward to trying to find some fossils of my own. . .

 

 

 

  

[Rock Noob]

10 minutes ago, ynot said:

Each site has its own collecting method, what works in one place may be useless in another site. 

When You get to an area do a surface search. look at the type of fossils and rock in the area. This should tell You if You should be splitting rock or screening or surface collecting or what ever.

If You are not sure You can always try different methods to see which will provide the best collecting.

 

Good luck!

Tony

I should start with what I'm always telling others to do- Google it!

 

Thanks for the advice, I bet one of my best moves would be to go there, take pics of likely stuff and return here for advice, or I might just get lucky and figure it out.

 

I know how "lucky" I generally am, though. . .