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Brachiopod? Trilobite? Id Requested Please :) Solved: Orthid Brachiopod!


jlhiowa

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Hello,


We went on our first fossil dig and I am hoping someone can help identify this fossil. Some of the people in our group thought it was a trilobite. However, I looked at pictures of trilobite fossils and they seem to have a 'face', whereas mine just has vertical lines. Thank you in advance :)


1. LOCATION

Vulcan Quarry in Sycamore, IL (Northern Illinois, Dekalb county)


2. GEOLOGY

* Silurian period

* Ordovician Period

* limestone

* dolostone


3. FORMATION

Here is the information on our handout: "The Quarry contains two ages of rocks: the Silurian Period (410 million years old) limestone which overlies the older Ordovician Period (approximately 450 million years old). Both rocks contain marine fossils in limestone and dolostone. Quarries from these time periods are known for marine fossils in limestone containing brachiopods, gastropods, corals, cephalopods, crinoids, and rarely trilobites. The top most layer of rock is composed of glacial till, leftover from when glaciers covered this part of Illinois."


4. ASSEMBLAGE of fossils also found at this location.

"marine fossils in limestone containing brachiopods, gastropods, corals, cephalopods, crinoids, and rarely trilobites."


5. DISCOVERY of specimen.

Not sure what to say. The quarry company spread out rocks for us.


6. CHARACTERISTICS that make you think it is a... whatever.

Some people on the dig thought it was a trilobite. I looked at trilobite images and my fossil doesn't have a 'face', just lines.

* This has an oval/rounded shape.

* There is a ridge along the outer edge.

* There are vertical lines after the ridge.



Thank you,

Jessica

post-15937-0-89372800-1405876663_thumb.jpg

Edited by jlhiowa
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maybe part of a brachiopod, I don't think it's a trilobite piece.

"Absence of evidence is not evidence of absence"_ Carl Sagen

No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go.

" I think, therefore I collect fossils." _ Me

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes

"can't we all just get along?" Jack Nicholson from Mars Attacks

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Im new to all this so correct me if im wrong but to me it looks like a brachiopod genus rafinesquina. I attached a picture i found online

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I was leaning towards brachiopod too. The only thing that throws me is the ridge/raised area along the outer edge.

When I look at pictures of brachiopods (and rafinesquina brachiopods, thanks Mufasa :) I don't see the ridge on the outer edge. Although maybe it's more common for the ridge to be worn away, and that's why I'm getting thrown.

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maybe part of a brachiopod, I don't think it's a trilobite piece.

Thanks for offering advice :)

Do you think I should try to break off the rock to see if it exposes more of the fossil? I just wouldn't want to accidentally break the fossil... so maybe it's better for me to leave it alone until I get more experience lol.

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That 'rolled & pleated' rim is pretty distinctive; I'm betting someone will recognize it. I can't even decide which fence to get on...

"There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant

“Try to learn something about everything and everything about something.” - Thomas Henry Huxley

>Paleontology is an evolving science.

>May your wonders never cease!

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It certainly looks like an orthid brachiopod. The attached example has similar features.

attachicon.gifIMG1.jpg

I think we have a winner!

"Absence of evidence is not evidence of absence"_ Carl Sagen

No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go.

" I think, therefore I collect fossils." _ Me

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes

"can't we all just get along?" Jack Nicholson from Mars Attacks

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Very interesting!

Would this rolled lip be the inner edge of the valve?

"There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant

“Try to learn something about everything and everything about something.” - Thomas Henry Huxley

>Paleontology is an evolving science.

>May your wonders never cease!

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Im sorry but from all the research im doing just now Orthid or Orthida refers to an order of brachiopods containing many genus.. Please enlighten me if im wrong:)

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Inner edge of the valve, Auspex

"Absence of evidence is not evidence of absence"_ Carl Sagen

No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go.

" I think, therefore I collect fossils." _ Me

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes

"can't we all just get along?" Jack Nicholson from Mars Attacks

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Im sorry but from all the research im doing just now Orthid or Orthida refers to an order of brachiopods containing many genus.. Please enlighten me if im wrong:)

That is correct. To identify the specimen further it would have to be cleaned to expose the inner surface (which is fortunately facing up in this case) to expose features such as muscle scars and supports for the lophophores.

Don

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