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minnbuckeye

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Recently, the opportunity presented itself to me to hunt for crinoids in the Burlington Formation of Des Moines County, Iowa. It was not a scheduled trip, but one that occurred because I in the right place  but the wrong time. My mistake gave me a full free day to hunt fossils in Iowa (what a bummer!!) , so I headed out to look for some crinoids. The Burlington is so different than any rock formation that I usually hunt. It is made up of 90% crinoidal remains. It must have been a spectacular ocean floor to see!! I envision it to have been an undersea garden. Fossils other than crinoids do show themselves and I did pick up a few.

 

First some brachiopods:

 

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A few corals. At least I think the larger one looks like coral. My doubts come due to its thinness. 

 

 

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 Trilobites are uncommon in the Burlington. This is the first trilo-bit I have ever found.

 

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There is a layer of fish pieces in the Burlington. Here are a few.2019-09-027.thumb.jpg.acf149e555b3bbd54fe81fdd4d1bb975.jpg2019-09-026.thumb.jpg.9bdfe0a8f250bbed83c057e3d976a1d7.jpg

 

 The next one is a partial tooth. I was working on some Devonian material before the Burlington. MAYBE this flew out of the pieces of Devonian I was breaking up. But it was noticed when I was splitting the fish pieces from the Burlington. @Elasmohunter, your thoughts????2019-09-027.thumb.jpg.acf149e555b3bbd54fe81fdd4d1bb975.jpg2019-09-026.thumb.jpg.9bdfe0a8f250bbed83c057e3d976a1d7.jpgDSC_0178-001.JPG.97f51980ebaf210e108a3bbd20e84897.JPG 

 

Can anyone explain the geological formation of this?? Crinoidal material on the surface, but the way it permeates the underlying matrix baffles me. The lower picture shows there is some slickenslide but the specimen in question seems different than that.

 

 

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I find many of these unkowns My guess is a plate from a crinoid cup?? But what species? They are large.

 

 

 

 

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Again, crinoidal pieces from what???DSC_0188-001.JPG.c16f29d94c66d6b258e87405b9c64a33.JPG 

 

 Occasional blastoids are found.

 

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Finally, the crinoids. Full calyxes are uncommon, but crinoid cups are abundant!! And crinoids can grow quite large:

 

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Here are some of the crinoid cups:

 

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 This cup was by far my largest:

 2019-09-116.thumb.jpg.3771b73ac3d067da49b8e8652b0d957e.jpg

 

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As you can see, I had a wonderful day playing in the Burlington. I suggest everyone  make a visit to it!!

 

Mike

 

PS, I have been trying to make proper IDs with marginal success. Please feel free to pipe in on anything you recognize, otherwise you may be seeing the same pictures in the Fossil ID Section!!!! Thanks

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I'm quite envious of your hoard of blastoids and crinoids!  :wub: :wub: :wub:  I've never visited the Burlington but I would sure like to.

@crinus knows the Burlington fauna well and he may be able to suggest some IDs.

 

Don

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Wow awesome trip. :envy:

Missouri's Burlington is fun to hunt but I've never hunted in Iowa's Burlington. I actually have family in Des Moines, so that may change soon. Some of those calyxs will clean up very nice it looks. And what great luck finding the trilobite pygidium. I've been lucky to only find a few here from MO, with the best being only half the trilo. Have you ever found one complete there?

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What beautiful rock!  Everything looks great, but I especially like those cute little blastoids - congrats!!!

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16 hours ago, minnbuckeye said:

 

 

Cann anyone explain the geological formation of this?? Crinoidal material on the surface, but the way it permeates the underlying matrix baffles me. The lower picture shows there is some slickenslide but the specimen in question seems different than that.

 

 

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Stylolites. Common/well known espec. for crinoids / echinoderms: https://en.wikipedia.org/wiki/Stylolite

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16 hours ago, minnbuckeye said:

There is a layer of fish pieces in the Burlington. Here are a few.2019-09-027.thumb.jpg.acf149e555b3bbd54fe81fdd4d1bb975.jpg2019-09-026.thumb.jpg.9bdfe0a8f250bbed83c057e3d976a1d7.jpg

 

 The next one is a partial tooth. I was working on some Devonian material before the Burlington. MAYBE this flew out of the pieces of Devonian I was breaking up. But it was noticed when I was splitting the fish pieces from the Burlington. @Elasmohunter, your thoughts????2019-09-027.thumb.jpg.acf149e555b3bbd54fe81fdd4d1bb975.jpg2019-09-026.thumb.jpg.9bdfe0a8f250bbed83c057e3d976a1d7.jpg 

I don't think this is a tooth.

Looks more like a fin ray of some kind of selachien.

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Nice finds! Definitely a little jealous.

Congrats on the trilobite! In my research, I never found any images of any from the Burlington, although they're definitely been reported. Van Tuyl (1923) mentions two potential genera from the Burlington (but he isn't certain of their identifications): Phillipsia sp. and Griffithides sp. Your trilobite may belong to one of these taxa.

I can confirm that the suture-like joints are, in fact, stylolites.

 

The 2-inch wide, partially damaged brachiopod is probably Spirifer sp. It may be Spirifer grimesi, but I think there are a few other large members of this genus present in the limestone too, so I'm not sure on that.

 

Another thing I'll draw your attention to is the dark green flecks scattered throughout the limestone. This is a mineral called glauconite; if it occurs in abundance, then it's interpreted as a slow-down in deposition or even a depositional hiatus. There are many layers in the Burlington that contain this mineral in abundance; some even contain enough to give the limestone a greenish tint.

 

The fish tooth that's embedded in the matrix resembles a cross-section of a cochliodont (Deltodus, Sandalodus, etc.), but without being able to see more, that's merely an educated guess. You should be able to release it from the matrix if you dissolve the limestone in acetic acid, but if it has any pre-existing cracks, then it will break, so be careful. It may be best to simply try an in-situ prep.

The spine is either a shark or "acanthodian" (stem chondrichthyan) spine.

The rounded tooth is probably a Deltodus sp., but differentiating it to species will not be the most fun thing ever. The document I sent you earlier should give you a good idea of where to start if you want to try.

Again, well done! Did you find any geodes too?

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Nice finds -- thank you for the photos. I fully enjoyed them.

 

 

Mark.

 

Fossil hunting is easy -- they don't run away when you shoot at them!

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Congratulations on a very productive day. I especially love all of the crinoid calyxes and those brachiopods. The fish material I'm sure is rare. I would love to check out that site someday.

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   @Khyssa, glad you enjoyed. If interested in anything, let me know as I owe you big time!!! 

 

 @Elasmohunter, if any of my finds can help your research, let me know and they are yours, except the trilobite. I accidentally destroyed it trying to remove some fish parts from its matrix!!!! Not a great moment. It was so subtle  , I didn't see it and just destroyed it getting to a black speck that turned out to be nothing identifiable. No geodes. Do you find geodes in the Burlington? I go down to Keokuk if I am collecting geodes.

 

 

 

 

 

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39 minutes ago, minnbuckeye said:

   @Khyssa, glad you enjoyed. If interested in anything, let me know as I owe you big time!!! 

 

 @Elasmohunter, if any of my finds can help your research, let me know and they are yours, except the trilobite. I accidentally destroyed it trying to remove some fish parts from its matrix!!!! Not a great moment. It was so subtle  , I didn't see it and just destroyed it getting to a black speck that turned out to be nothing identifiable. No geodes. Do you find geodes in the Burlington? I go down to Keokuk if I am collecting geodes.

 

 

 

 

 

Thank you so much! If I can use anything, then I will definitely let you know.

I think the Burlington contains occasional (albeit rare) geodes, but they're best known from the geode bed under the Warsaw Shale. When I've been out collecting in the area, we typically get distracted by them and bring back far more than we could ever use. . . . ;)

Alas about the trilobite! Most of the vertebrate remains (~95%?) end up being unidentifiable anyways. But at least you have photos. Any chance you could repair it?

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@Elasmohunter  Hit it with a hammer and you know how friable some of the Burlington is. It just crumbled. On a positive note, the one tooth posted embedded in the matrix has turned out to be quite large. Only a fraction of it was showing!! I will get you a picture when I finish prepping it. I am going to leave it in some matrix. I like fossils that way!

 

 @Pemphix, thanks for your ID!!!! Wasn't sure what it was.

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