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An Eocene summer


jpc

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It was a busy summer, and now it is snowing.  I got out a few times this summer and here is my report for y'all's enjoyment.  

 

Most of my outings were into Wyoming's early Eocene.  Way back in the spring I went to a newly discovered mammal site.  I showed one jaw here: 

 Here is a view of the site.  This is the early Eocene Wind River Fm in central WY.  (Wasathcian in age). Lots of land to look at out here, and I have only prospected a wee bit of it.  My pack is down thereon the flats... let's see if we can find any fossils down there. 

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OH, look... a mammal jaw.  And can you find an additional bonus tooth in there?

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Right next to this there were a group of crocodile bones.  Again... find the bones.  

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I dug around quite a bit to try to find the source of these bones and got totally skunked.   

 

I usually get out into the Eocene beds of southwest WY on Labor day, but this year it happened a month late, so here are some pix from the first weekend of October.  It starts getting cold at this time of year.   The first photo is me at an abandoned oil well site where the oil folks had scraped up a limestone layer in their bulldozing.  The layer has bones in it... mostly turtle pieces and lots of very small (and practically un-prepable) fish bones.  If you break rocks long enough you will find good stuff. 

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Below are a the best things I found on this visit.  For those interested, these things are prepped with ye ole air abrasive under the microscope.  Dolomite at about 20 psi.  There is potential for the air abrasive to abrade the bones and I am not sure if these teeth got overly air abraded or are suffering form Eocene erosion.  It is very slow prep, so I don't focus too much on this layer. First a little croc dentary.  Note that the bone runs off the edge of the rock.  I spent a long time looking for the rock that contains the rest of this jaw... again, skunked.  But this is a good little find.  The empty roundish area to the right of the jaw is the impression of a snail.  fresh water snails of the genus Physa are the most common fossils.

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This next bone is the angular bone of a small croc.  The angular is one of the bones in the lower jaw. 

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The limestone layer is in the Wasatch Formation.   After busting up enough rocks, I went to one of my favorite sites about a half mile away.  Also in the Wasatch Fm.  This layer sits just above the same limestone layer that I collected at the oil well site.  Here I am digging.  Note the weather is getting nicer; I have jettisoned the coat. This site is full of small randomly distributed fossils.  Again, mostly turtle pieces, but also some good croc material and occasional mammal teeth and jaws.    

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And here is a distant view of the quarry.  The limestone with bones is seen as an small cliff just below my backpack.  

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So, let's look at a few fossils.  First an emerging soft shelled turtle piece ( a costal plate).  That is a dental pick for scale.  The digging here is best done slowly so you don't break the bones.  You can see other pieces of bones in here.

 

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The first photo in the next post is the same turtle piece fully exposed.

 

 

 

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Here is a little croc vert.  

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...and here it is all prepped out.  This stuff preps with the air abrasive also... but sodium bicarb at about 40 psi. Even less for really delicate things like the lizard jaw below.  But they also tend to be well cracked up and I might need to do a lot of microscopic gluing.   

 

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I just prepped this one today.  I had it labeled as 'mammal jaw?' but it turned out to be a strange little lizard jaw.  I was very intrigued and actually looked it up.  I am calling it Restes rugosus.  It has typical lizard teeth in the rear and a very croc-like tooth up front.  

 

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I did not take this one apart and glue it together to undo the cracks.  Maybe another day.

 

A number of years ago I found some large croc pieces in this quarry.  I think they are all part of one animal.  This spring I actually got around to prepping its jaw.  Here is it the jaw after I exposed it in the plaster jacket I collected it in.  Notice the bonus vertebra tucked in under the jaw.  I think I collected this at least ten years ago.

 

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And here it is prepped, as seen form the other side.  This one I did take all apart.  A challenging project.  It is pretty beat up.  Notice the round divot near the right end where the vert was pushed into the bone... soft-sediment deformation

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After a day at this site, I went to another site about an hour away.  Now we are going upsection (a bit younger).  Into the Washakie Formation (Bridgerian Age).  I neglected to take any shots of the scenery, but I found this.  This is cool. 

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A large mammal jaw.  Here it is all prepped.  (I used  epoxy putty to fill in the gaps. )  I am calling this one Hyrachyus, a rhino.  I am not certain about that ID, but it is most definitely a perissodactyl. 

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Not far from the jaw was a partial croc skull... a much bigger animal than the the ones represented by the small bones above.  I am now prepping this one, but here is what it looked like as I was unpacking it.

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Thanks for listening.

 

I love the Eocene.

 

Stay Tuned....

 

 

 

 

 

 

 

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Wonderful.

It would be such fun hunting in those locations. 

Such a variety of vertebrate life.

Thanks for sharing the adventures, photos and finds. :)

Life's Good!

Tortoise Friend.

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Hi JP,

 

If you can get a shot of your Hyrachyus jaw straight down at the biting surfaces of the teeth, Fossillarry can identify it.

 

Hyrachyus has been called an early rhino or at least a close relative of early rhinos, or more technically "a basal rhinocerotoid."  I don't know what the consensus is now.  I think Fossillarry would agree with you.

 

Jess

 

@fossillarry

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OMG. This post made my morning. I can't wait to see more! :popcorn::popcorn::popcorn:

That little lizardy jaw just tickled me pink. I am headed out in about an hour to go fossil hunting in the Aquia Formation today. This was a nice warm-up.

 

Thanks for all of the field photos. What beautiful country! 

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Awesome stuff, thanks for sharing!

“...whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved.” ~ Charles Darwin

Happy hunting,

Mason

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@jpc Thanks very much for sharing your passion with us. You certainly do need a lot of patience to work these layers by the looks of it. And the preparation work seems to be akin to that of a jewelers. You must have the patience of a saint.

 

Greetings from the Lake of Constance. Roger

http://www.steinkern.de/

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Fascinating report, great pictures, and very interesting finds. I can appreciate more fully your extensive work in revealing these small, but exquisite specimens. Slowly, life of the Early Eocene is coming to light thanks to your efforts.  Thanks for sharing this with us. 

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Beautiful pics and finds :yay-smiley-1:love the tiny croc material and that rhino jaw is stellar 

Every once in a great while it's not just a big rock down there!

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Great report! I keep threatening the wife with a road trip out west. Beautiful country and beautiful fossils. Thanks for sharing! :) 

The good thing about science is that it's true whether or not you believe in it.  -Neil deGrasse Tyson

 

Everyone you will ever meet knows something you don't. -Bill Nye (The Science Guy)

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Those are some really fantastic finds! I'm sure there was quote a bit of searching and digging requied but you've done a good job preserving what you found. The jigsaw puzzle that is that basal rhinolike critter's jaw looks like it took a lot of patience to reassemble.

-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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