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Spence Shale (Idaho) Fossils


davehunt

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I am trying to catch up on my fossil trip reports this Christmas break and what follows is a trip from Sept 2010.

After a great deal of research, I made an attempt at finding a Spence Shale outcrop in SE Idaho in in 2009. Turns out I got within a 100 meters, but missed it. There are some dense woods around it. I had better luck last summer and had a chance to spend several hours at the site. The Spence Shale is part of the Langston formation and Middle Cambrian in age (513-499 mya). I believe Charles Walcott originally surveyed the area in the late 1800s. He also found the Burgess Shale.

The matrix is very crumbly and it is difficult to get anything that resembles a "plate". The biggest piece I brought home is barely 6 inches across. Lots of fragments/heartbreakers, but a very interesting location.

Scale measure is in centimeters/millimeters.

I welcome any input on species. I'm mostly going off a couple sites that have Spence Shale material, not any sort of expertise on my part.

I have about 20 images to post, so give me a few minutes to get everything up as a group.

Dave

Image 1: plate with lots going on

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Image 2: trilobite from the center of plate - probably Amecephalus idahoense (Resser, 1939)

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Image 3: A spine from the upper right portion of the plate in Image 1

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Image 4: A mortality grouping of agnostoids from same plate. I think these are Peronopsis brighamensis (Resser, 1939a)

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Image 12: cast of Amecephalus idahoense (Resser, 1939)?

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Image 13: unknown soft bodied creature?

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Hyolithes are pretty cool. See the Wikipedia article on them. Some think they are their own phylum. They are hard to photograph as they mostly manifest as shiny surfaces.

Image 16: Hyolithes sp. This is a typical find (found lots and lots of them).

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Image 17: This is a giant Hyolithes sp. Coming in at about 4cm long.

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Edited by davehunt
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Final images.

Image 18: I think this is a pair of Zacanthoides idahoensis (Walcott, 1908)

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Image 19: Zacanthoides sp. ?

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That's it. Thanks for looking.

Dave

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Hefty haul of trilobites Dave... the unknowns (images 7 & 8) appear to be the dorsal and ventral cranidia of Amecephalus idahoense. A superb paper was recently published addressing Zacanthoides taxonomy and I'm forwarding a copy since you found so many great examples. Congrats and thanks again for posting! :D

image.png.a84de26dad44fb03836a743755df237c.png

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Thanks so much for composing and posting this; seeing the little-known is exciting!

"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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Great report and finds, Dave! :):wub:

Thanks for posting them!

Regards,

    Tim    -  VETERAN SHALE SPLITTER

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thanks everyone. Squalicorax: yes, same spot you were recently at. The creek was low when we were there and we just took it slow over the rocks.

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Great finds Dave. Thanks for sharing with us. I have been getting interested in the Spence since getting a few bugs from their in my collection. Yours are nice!

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Wow! Those are some cool fossils. I've wanted to search the Spence Shale and had a chance a few years ago but decided to head south instead towards the House range in Utah. I'll get back that way someday. Thanks for the inspiration. :)

-Dave

__________________________________________________

Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPhee

If I'm going to drive safely, I can't do geology. - John McPhee

Check out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/

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  • 1 year later...

great finds, talking to some locals when we went, if you dig in deep past all of the loose shale (2 or 3 ft), you can pull out unbroken material that isnt as brittle

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