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Local Ordovician Trip


minnbuckeye

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It has been 7 years now since I became hooked on the "fossil thing". My hunts seem to creep a little further from home with each passing year. Greener pasture syndrome. So a few days ago, I purposely started my adventure close to home. Here are a few finds from the Ordovician. @ClearLake

 

Let me start with a few unknowns: 

 

2020-09-034.thumb.jpg.82b866a6d0e080eaff3af0fa427886de.jpg 

2020-09-035.thumb.jpg.ec012bef0570b63e0a199ec3d81f94bf.jpg

  

2020-09-011.thumb.jpg.b43e3671b417e298440fb17eff696f21.jpg 

This last one could just be a squished brachiopod, but seems to be a coiled organism.   

 

DSC_0965-001.JPG.4f838671003bdbfb1ced99f87ec4db47.JPGIDed as Trilobite eye, probably Isotelus

 

The pygidium pictured came from a new spot I tried, expecting to find Isotelus. The pygidiums look more like Bumastus???? Actually IDed as Homotelus(?) florencevillensis.

 DSC_0983-001.thumb.JPG.bd63079b84bdb1fe5fc353896e7ca428.JPGAgain, not Bumastus, but Homotelus(?) florencevillensis.DSC_1037-001.thumb.JPG.3e0ae1020ad2d4af67b8b4bc13729570.JPG 

The trilobites came from the Maquoketa, the others from the Galena. 

 

 I collected a few brachiopods (Galena) to please @Tidgy's Dad

 2020-09-023.thumb.jpg.5b38e991e1d9778f88d15aff6739754d.jpg2020-09-024.jpg.cc5aa8ca0d1cc447707047d1d1e84596.jpg2020-09-025.thumb.jpg.91afba8121d1a04376eced40dadf41de.jpg

  

The Galena locally has many gastropods. 

 

 2020-09-026.thumb.jpg.7ac6ad8e99919490827076cc9dfb3748.jpg

 

 

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1 hour ago, minnbuckeye said:

It has been 7 years now since I became hooked on the "fossil thing". My hunts seem to creep a little further from home with each passing year. Greener pasture syndrome. So a few days ago, I purposely started my adventure close to home. Here are a few finds from the Ordovician. 

 

Let me start with a few unknowns: 

 

2020-09-034.thumb.jpg.82b866a6d0e080eaff3af0fa427886de.jpg 

2020-09-035.thumb.jpg.ec012bef0570b63e0a199ec3d81f94bf.jpg

  

2020-09-011.thumb.jpg.b43e3671b417e298440fb17eff696f21.jpg 

This last one could just be a squished brachiopod, but seems to be a coiled organism.   

 

DSC_0965-001.JPG.4f838671003bdbfb1ced99f87ec4db47.JPG

 

1) pyritisized Crinoid (?)

2) Graptolith

3) Brachiopod

4) Trilobite eye (?)

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The first unknown seems to be a crinoid.

Agree with graptolite. 

I don't think the third one's a brach. Don't know what it is, though. How big? 

I would say the trilobite pygidia are Bumastus. 

Love the brachipods, so thanks for that.:b_love1:

 

 

 

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I had a disappointing day on trilobites, only partials. Locating the Maquokota layer with the Isotelus means finding graptolites as seen in this picture 

 

 DSC_0976-001.JPG.890b9b40c2c71cbec6e984e840987d67.JPGDSC_0968-001.JPG.e8ff58f6e49ea7ed22875596c2439a38.JPGDSC_0986-001.thumb.JPG.4a75f85743d980293ef1c97f0ab2434e.JPGDSC_0988-001.JPG.648862bb127a28b67457cf1a4ca5bfc7.JPGDSC_1015-001.thumb.JPG.aa0333f429115c0052e3eaa250550b73.JPGDSC_1035-001.JPG.0f95f118984a666c7a63712b3b743089.JPGDSC_1043-001.JPG.7ac6bfc2bbbfeb3d12d126d1086be403.JPG 

 

And finally the most frustrating find of the day! The negative shown here came with a perfect positive(cephalon too!!!). What I didn't realize was the positive was chipped away and loose on the other piece. So as I picked up the rock, the trilobite fell into a deep crack between the rocks. After spending an eternity looking for it, I took the negative and headed out. DSC_1036-001.JPG.d1d8b30bfaed6e8c45b6022f73da0215.JPG

 

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6 minutes ago, Tidgy's Dad said:

I don't think the third one's a brach. Don't know what it is, though. How big? 

I would say Bumastus. 

 

As far as I know Bumastus hasn't such prominent ridges on its Pygidium (?). Bumastoides porrectus has very slight ridges, but not as straight as visible here. Better to compare it with those:

2020-09-023.jpg.b1be1092acd1d75120247fd654bcc085.jpg

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The brachs maybe :

Top left Strophomena filitexta, though the one with the flat face far top left maybe Oepikina minnesotensis. 

Top right, Cincinnetina meeki and below the on the right Sowerbyella sp. The one bottom left maybe Pionodema? 

I think the tiny gastropod is Hormotoma gracilis. 

 

 

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1 hour ago, Johannes said:

As far as I know Bumastus hasn't such prominent ridges on its Pygidium (?). Bumastoides porrectus has very slight ridges, but not as straight as visible here. Better to compare it with those:

2020-09-023.jpg.b1be1092acd1d75120247fd654bcc085.jpg

Those are strophomenid brachiopods. :headscratch:

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1 hour ago, Johannes said:

I Know. :zen:

Ah, I see. We are talking at cross purposes. 

1 hour ago, Tidgy's Dad said:

The first unknown seems to be a crinoid.

Agree with graptolite. 

I don't think the third one's a brach. Don't know what it is, though. How big? 

I would say Bumastus. 

Love the brachipods, so thanks for that.:b_love1:

 

 

 

I referred to the first photo in my first line. 

The second photo in my second line. 

The third photo in third line. 

And the unidentified pygidia in my fourth line. 

Sorry for the confusion, I have edited my original post to make it clearer. 

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18 minutes ago, Tidgy's Dad said:

Ah, I see. We are talking at cross purposes. 

I referred to the first photo in my first line. 

The second photo in my second line. 

The third photo in third line. 

And the unidentified pygidia in my fourth line. 

Sorry for the confusion, I have edited my original post to make it clearer. 

Object in 3rd and both in 4th line are the same (?). The 5th line may show a trilobite eye.

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1 hour ago, Johannes said:

Object in 3rd and both in 4th line are the same (?).

Oh, good grief. :rolleyes:

He posted posted 3 pictures of the crinoid, grouped together in one 'photo'. 

Then three photos of the graptolite in one image. 

The third block was three photos of the 'brachiopod'. My third line. 

The fourth line refers to all the trilobite pygidia that occur later. 

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Ok, now we are fine and under a shared umbrella of agreement. Exept about the "Brachiopod thing". :)

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1 hour ago, Johannes said:

Ok, now we are fine and under a shared umbrella of agreement. Exept about the "Brachiopod thing". :)

:beer:

I'm not sure about the brachiopod thing. i'm not arguing there, either. :)

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Fifi says you share a nice umbrella, all is well that ends well with smart people.

Fifi loves you both.

 

Nice finds minnbuckeye, fifi is sorry for the loss of your trilobite.

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Greener pasture syndrome... a very succinct way to describe what I’m sure many of us experience. Nice finds still :brachiopod:

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These are not Bumastus or Bumastoides.  The course of the facial suture matches better with an isoteline, similar to the attached figure of Homotelus(?) florencevillensis from the Maquoketa of Iowa.  I added the question mark as there is some ongoing taxonomic work regarding the best generic classification.

 

Amati 2014:

"Homotelus was erected by Raymond (1920) for isotelines lacking genal spines but with wide cranidia, weak axial furrows, elevated palpebral lobes and a lateral border. Jaanusson (in Moore, 1959) added that a frontal area is lacking and the palpebral lobes are positioned slightly in front of the transverse mid-line of the cranidium. Whittington (1950) noted that the differences between Homotelus and Isotelus are small and recommended restricting the genus to the type. I agree that the genus should be restricted but feel that the lack of a frontal area on the cranidium allies Homotelus more closely with Vogdesia than Isotelus. Some species previously assigned to Homotelus (e.g., H. bromidensis, Esker, 1964) may belong in Vogdesia."

 

image.thumb.png.eae8261eb43d78b1a1db61e8ccdc86a3.png  image.png.9cc2fb5bf2c6f8d7c53cb62892cfee65.png

 

Walter, O.T. 1924

Trilobites of Iowa and some related Paleozoic Forms.

Iowa Geological Survey Annual Report, 31(1):167-390  PDF LINK

 

Amati, L. 2014

Isoteline Trilobites of the Viola Group (Ordovician: Oklahoma): Systematics and Stratigraphic Occurrence.

Oklahoma Geological Survey, Bulletin 151:1-125  PDF LINK

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Those are some nice trilobites (and other items) Mike!  I look forward to hunting for similar items!!

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I was about to say even if they are partials, the trilobites are nice! They seem to be pretty abundant there, or maybe you just got lucky! The brachs are pretty sweet too, the beekite one is my favorite.

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On 9/10/2020 at 8:55 AM, minnbuckeye said:

Actually IDed as Homotelus(?) florencevillensis.

 DSC_1037-001.thumb.JPG.3e0ae1020ad2d4af67b8b4bc13729570.JPG

 

This paper provisionally applied the name Vogdesia suggested by Amati 2014:

 

Carlucci, J.R., Westrop, S.R. 2015

Trilobite biofacies and sequence stratigraphy: an example from the Upper Ordovician of Oklahoma. Lethaia, 48(3):309-325 

 

Pending a more thorough formal description, I would tentatively label these: Vogdesia? (=Homotelus) cf. florencevillensis emo73.gif:P

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Very impressive trilobite finds and I like the variety! 

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I love the rock with the Isotelus pygidium and graptolite - what a nice association piece! :wub:

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  • 11 months later...

Some additional taxonomic confusion needs to be addressed. Amati 2014 suggested that some species of Homotelus including H. bromidensis might be synonymous with Vogdesia, but unfortunately did not recognize the previous synonymy of Shaw 1974. Fortunately someone has recently pointed out that Shaw 1974 had already synonymized Homotelus bromidensis with Vogdesia.

 

 

image.png.cc0b151f7c3c37872b17a9aa756c11f4.png

 

Shaw, F.C. 1974
Simpson Group (Middle Ordovician) Trilobites of Oklahoma.
Journal of Paleontology 48(5) Supplement: Memoir 6:1-54

 

 

"Homotelus was erected by Raymond (1920) for isotelines lacking genal spines but with wide cranidia, weak axial furrows, elevated palpebral lobes and a lateral border. Jaanusson (in Moore, 1959) added that a frontal area is lacking and the palpebral lobes are positioned slightly in front of the transverse mid-line of the cranidium. Whittington (1950) noted that the differences between Homotelus and Isotelus are small and recommended restricting the genus to the type. I agree that the genus should be restricted but feel that the lack of a frontal area on the cranidium allies Homotelus more closely with Vogdesia than Isotelus. Some species previously assigned to Homotelus (e.g., H. bromidensis, Esker, 1964) may belong in Vogdesia."

 

Amati, L. 2014

Isoteline Trilobites of the Viola Group (Ordovician: Oklahoma): Systematics and Stratigraphic Occurrence.

Oklahoma Geological Survey, Bulletin 151:1-125  PDF LINK

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