Cambrian Unknown

[minnbuckeye]

Last week I had the intentions of going fishing. Unfortunately just as I got to the boat landing, it began to rain so I decided to unhook the boat  and run over to a road cut 20 miles away to see if winter had brought down any new rocks to bang on. I spent about 15 minutes at the site and learned quickly NOT to look at sandstone in the rain. Samples  turn to sand in your hand!!! This site is Eau Claire formation / Cambrian strata. Trilobites are what I was looking for. Here are a couple of typical hash plates from the site that I was able to save:    

 

 

    

 

 

What I have questions about are these "cephalopod like" structures seen in this photo:

 

 

 

Any info on these structures would be appreciated. I have never ran into these at this site before. They taper like a cephalopod, but no obvious septa, might be because sand does not preserve the chambers well???

Hope to hear from you.

 

 Mike

P.S. The rain eventually quit and I was able to fish.

[Peat Burns]

Hyoliths?

[minnbuckeye]

Interesting possibility. I had never heard of a Hyolith before.

 

[piranha]

Hyolithes primordialis is a common Eau Claire species of hyolith.  

Congrats on the excellent mass assemblage of Cedaria woosteri.

 

 

[minnbuckeye]

3 minutes ago, piranha said:

Hyolithes primordialis is a common Eau Claire species of hyolith.  

Congrats on the excellent mass assemblage of Cedaria woosteri.

 

 

I would not have been able to make ID without everyone's help and am more knowledgeable now than when I woke up this a.m. So it is a good day! But at my age, no guarantee I will remember it in the morning. Thanks! By the way, these types of hash plates are as common here as brachiopod hash plates are in our Ordovician areas. Now fining a complete Cambrian trilo takes lots of time.

[Wrangellian]

Nice samples from a location you don't hear about much. My first thought was Hyolith too - if you're familiar with Cambrian fauna certain things jump out at you. Good luck on finding the complete trilo, will be watching this space.

[fifbrindacier]

Nice finds, congratulations.

[EMP]

3 hours ago, minnbuckeye said:

Last week I had the intentions of going fishing. Unfortunately just as I got to the boat landing, it began to rain so I decided to unhook the boat  and run over to a road cut 20 miles away to see if winter had brought down any new rocks to bang on. I spent about 15 minutes at the site and learned quickly NOT to look at sandstone in the rain. Samples  turn to sand in your hand!!! This site is Eau Claire formation / Cambrian strata. Trilobites are what I was looking for. Here are a couple of typical hash plates from the site that I was able to save:    

 

 

    

 

 

What I have questions about are these "cephalopod like" structures seen in this photo:

 

 

 

Any info on these structures would be appreciated. I have never ran into these at this site before. They taper like a cephalopod, but no obvious septa, might be because sand does not preserve the chambers well???

Hope to hear from you.

 

 Mike

P.S. The rain eventually quit and I was able to fish.

 

First couple are trilobite hash plates. The last ones are Saltarella sp. cones.

[piranha]

2 hours ago, EMP said:

...The last ones are Saltarella sp. cones.

 

 

Salterella is not reported at Eau Claire.  As I mentioned above, Hyolithes primordialis is a common hyolith from the Eau Claire Formation:

 

text from:

 

Huber, M.E. (1975)
A paleoenvironmental interpretation of the upper Cambrian Eau Claire formation of West-Central Wisconsin.
M.S. Geology Thesis, University of Wisconsin-Madison, 110 pp.

 

Hyolithes primordialis 

Description: A conical shell with a sub-triangular cross-section. Growth lines present on the exterior.  No apparent ribs. Molds of operculum present but unattached.  Sub-trigonal in shape.  Considering the great concentrations of the hyolithids on bedding surfaces and shell material (brachiopod) that is found in the sediment filling the molds of hyolithids in the Eau Claire Formation, it is my opinion that these accumulations are the result of sediment transport and do not represent a biocoenose.  However, I do not feel that the amount of transport has been great.  These unoccupied shells are fragile and yet in most instances they are fairly complete.  Some specimens are missing the apex.

 

 

Hyolithes primordialis from the Eau Claire Formation:

 

figure from:

 

Walcott, C.D. (1916)
Cambrian Geology and Paleontology III, Cambrian trilobites.
Smithsonian Miscellaneous Collections, 64(3):157-258

[Darktooth]

Nice trilo hash plates! Very cool!

[Oxytropidoceras]

piranha wrote:

 

"text from:

 

Huber, M.E. (1975)

A paleoenvironmental interpretation of the upper Cambrian

Eau Claire formation of West-Central Wisconsin.

M.S. Geology Thesis, University of Wisconsin-Madison, 110 pp."

 

A PDF file of this thesis is at http://digital.library.wisc.edu/1793/11416 .

 

Also, there is:

 

Robles, M.R. (2012)

Geochemical and Taphonomic Analysis of Very Well-Preserved

Late-Middle Cambrian Lingulid Brachiopods From Laurentia

M.S. Geology Thesis, University of California, Riverside. 78 pp.

http://escholarship.org/uc/item/7zp0v74d

http://escholarship.org/uc/item/7zp0v74d#page-1

 

Great trilobites, great picture. Thanks for posting.

 

Yours,

 

Paul H.

[Darktooth]

@minnbuckeye I really have to thank -you for posting this. I also recently found my first Hyolith, at Deep Springs Road and had no idea what it was until I read this. I had never heard of one before. At first when I found mine I thought it was maybe a Devonian fish tooth. But after looking in my new Devonian field guide, I could not find any fossil what so ever that matched it. Then I saw the pics in this post and thought it looked similar.Then I looked up google images for Hyoliths and that's for sure what it is. Here is a pic of mine.

[minnbuckeye]

Yours is prettier than mine!! Sandstone does not preserve detail well. Great find. Fossil of the month? Never saw one on TFF before.