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Another First For Me From Austin Chalk - But What Is It?


surfergirlatx

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Today I went to a place in the middle of NO WHERE...no cell signal...no humans...kinda scary to be all alone, in a creek...anyway..off topic. I found this fossil. I think I may have a clue as to what it is, but of course I wanted to ask the forum for their assitance pretty please.

Cretaceous, Central Texas.

#1. post-6873-0-08668900-1328762027_thumb.jpg

#2. post-6873-0-64986000-1328762034_thumb.jpg

#3. post-6873-0-80417000-1328762042_thumb.jpg

#4. post-6873-0-41880700-1328762050_thumb.jpg

Thanks for your assistance.

Kim

Edited by surfergirlatx

"The road to success is always under construction." Author Unknown.

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I did a google image search for Cymatoceras and well...some match and some dont...Half the images show the "lines" being too close together, while the specimen I have the "lines" are further apart?

Conflicting interent websites :(

"The road to success is always under construction." Author Unknown.

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Hello surfergirlatx. (is this your right name?)

nice found, and thanx for showing!

I think your natiloid is an Eutrephocers sharpei. i'm sure about the surface is smooth without this fine ribs like Cymatoceras.

The suture makes a soft "S" on the venter.

Look here: http://www.mineralie...on?fossilid=263

scroll a litte bit down, so you can compare the surface between Cymatoceras and Eutrephoceras.

It can bee from the turonian, did you have any other macrofossils from this spot?

greez, karl

post-7943-0-62423700-1328774566_thumb.jpg

I want to die sleeping like my grandfather, not screaming like his passenger!

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Kim,

Karl probably has it correct as a Eutrephoceras. There is a species E. campbelli known from the upper Austin Chalk as well as two others from higher up in the Navarro. These can be pretty common at some locations but are often all squashed or busted up. Looks like you found a fairly decent one.

Erich

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I did a google image search for Cymatoceras and well...some match and some dont...Half the images show the "lines" being too close together, while the specimen I have the "lines" are further apart?

Conflicting interent websites :(

The difference between line spacing is whether you're seeing ribs or sutures. On cephalopods with thicker shells the ribs show more prominately on the outside surface like on an external cast. When you see the wider spacing it's the sutures from an internal mold, Some (lucky) times a fossil will have both, with either translucent shell you can see sutures through or cast shell broken away on part of the specimen showing sutures underneath.

Nice 'loid!

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Hello surfergirlatx. (is this your right name?)

nice found, and thanx for showing!

I think your natiloid is an Eutrephocers sharpei. i'm sure about the surface is smooth without this fine ribs like Cymatoceras.

The suture makes a soft "S" on the venter.

Look here: http://www.mineralie...on?fossilid=263

scroll a litte bit down, so you can compare the surface between Cymatoceras and Eutrephoceras.

It can bee from the turonian, did you have any other macrofossils from this spot?

greez, karl

Thank you Karll for you help with my natiloid! Its certainly does appear to be a Eutrephocers sharpei. The Cymatoceras seem to have much thinner spacing in its either ribs or sutures. As far as finding other macrofossils from this location....they ONLY other fossil that were there were oysters. That is why I thought this natiloid was so special and somewhat out of place.

The entire river bed that I hunted yesterday was solid oysters. As I attempted to take pictures of the location, I noticed my camera didnt have its memory card in it, so I had to use my cell phone.

This natiloid was just hanging under a large limestone slab all alone. I have never found one before, hence my excitement.

Also, surfergirlatx is my screen name, my real name is Kim :)

Here are a few pics from my cell phone of the area:

post-6873-0-09811800-1328808393_thumb.jpg post-6873-0-39316500-1328808396_thumb.jpg

post-6873-0-32337400-1328808401_thumb.jpg post-6873-0-39301900-1328808405_thumb.jpg

Kim,

Karl probably has it correct as a Eutrephoceras. There is a species E. campbelli known from the upper Austin Chalk as well as two others from higher up in the Navarro. These can be pretty common at some locations but are often all squashed or busted up. Looks like you found a fairly decent one.

Erich

Thanks for looking Erich. I also think Karl is correct with his ID! I was so excited to find it there all by itself in a sea of oysters :)

The difference between line spacing is whether you're seeing ribs or sutures. On cephalopods with thicker shells the ribs show more prominately on the outside surface like on an external cast. When you see the wider spacing it's the sutures from an internal mold, Some (lucky) times a fossil will have both, with either translucent shell you can see sutures through or cast shell broken away on part of the specimen showing sutures underneath.

Nice 'loid!

BobWill, Thank you for explaining what the "lines" I am seeing represent. That really helps!!! Next time I visit this spot, I will be sure to take my camera, with its memory card!!!!!

I was just happy to get the genus...let alone the species! Not that I have a real reason for needing this information....but ever so happy to have it to add to my database/ID card for this specimen!

Thanks again to all!!!

Kim

Edited by surfergirlatx

"The road to success is always under construction." Author Unknown.

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Hello Kim.

This nautiloid are often found in our area.

Greets Karl

I want to die sleeping like my grandfather, not screaming like his passenger!

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Kim,

The new photos are interesting. How close are they to where you were collecting the other stuff? The first photo looks like an Exogyra and the third looks like Pycnodonte aucella. The second has both going on. The P. aucellas put you higher(younger) in the Austin Group. Maybe Dessau Formation.

Oh wanted to add: take every image you find on the internet with a grain of salt. If it's out of a scientific paper or publication it might be fine but there is plenty of stuff with the wrong names thrown up by other amatuers (takes one to know one) on the web.

Edited by erose
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Kim,

The new photos are interesting. How close are they to where you were collecting the other stuff? The first photo looks like an Exogyra and the third looks like Pycnodonte aucella. The second has both going on. The P. aucellas put you higher(younger) in the Austin Group. Maybe Dessau Formation.

Oh wanted to add: take every image you find on the internet with a grain of salt. If it's out of a scientific paper or publication it might be fine but there is plenty of stuff with the wrong names thrown up by other amatuers (takes one to know one) on the web.

All the oysters are like that on each bank all mixed in together but totally stuck in the matrix....its INSANE!

"The road to success is always under construction." Author Unknown.

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