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Oreodont Prep Series


snolly50

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Forum member Ray Eklund recently offered several pieces of White River mammal material at auction to benefit the Forum. I was pleased to win one of these and received it a little over two weeks ago. I now hope to post a series attempting to show the progress in preparation.

This fossil is the skull and lower jaw of Merycoidodon gracilis. This is one of the smaller Oreodonts, about the size of a modern red fox.

Ray provided the following collection information: Brule Member of the White River Formation, Sioux County, Nebraska.

Here are photos provided by Ray, posted for the auction. The remainder of the photos in this series were shot with a Nikon D600 with a 50mm, 1.8 lens mounted. These photos were processed in Photoshop Elements 11 and are greatly reduced in size/resolution for posting.

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Here is a first look at the critter and formulation of a prep plan (We'll see how that goes!)

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Below prep has started, using an Xacto blade and a pin vise with a carbide needle, triangular point. Simply scraping at the thin areas of matrix.

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Edited by snolly50
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Hey Snolly are these two different skulls?

Edit, I mean this post and this post

Same skull, different angle, different light. I just tried to upload part III, but it choked on me. I'll try again in a minute.

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At the time of the auction Forum member jpc opined "leaving the matrix as a natural stand" would make for a great display. He was right, but inspection of the piece revealed already existing separation of the matrix/lower jaw. It was determined that it would be more prudent to completely free the piece from matrix. In order to get the matrix down to a size/thickness that could be worked with precision a saw was employed. Preppers with air powered scribes would probably employ those devices at this point.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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OOPS!!!!

Reduction of the matrix allows more precision and places less stress on the fossil itself during the final prep. However, in this case the desire of the fossil to be free of the matrix was too great. Now that's a good thing, as it gets rid of a lot of matrix in one swoop. Unfortunately the matrix often invades the fossil material itself and when the matrix breaks away rather than being removed by cutting/abrasion - Disaster. Here is the fossil after the block of matrix released from the stress of sawing. Note the two large shards of bone at the middle, left broken away from the dentary/lower jaw. OUCH!

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I remembered not to panic. I used gel type "superglue" for this type of damage. You will see in future pictures that the repaired area doesn't fit "tightly." This is because the matrix had invaded the bone and it was lifted slightly from the rest of the jaw.

Remember; You can't make an omelet without breaking a few eggs.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Her smile is starting to emerge!

At this point we can see that this will be a very nice Oreodont fossil. It is relatively complete. Missing are the zygomatic arch, bilaterally. Typically, most of the premaxilla and incisors are gone. The large upper canines are also "mostly" MIA.

During the prep a 1/16 x 1/8" chunk of molar had to be reattached, as did a 1/4" piece below the orbit. Keep the glue handy.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Can't wait to see it when your done Snolly!!!! I find the thought of prep work like this very intimidating... I'd be afraid if I bought something like this I wouldn't do it justice! Glad she's in good hands!!! :)

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I have a mental picture of what this fossil looks like. However, I think it's very helpful to have a large visual prompt in the prep area. It helps point out those little nooks and crannies, those unexpected features.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Bring on the Electrostylus! I like this instrument and it cuts/pulverizes this soft, granular matrix with ease. Using the "high" setting you can chip off good sized chunks of matrix. On low you can use it next to the fossil itself with little worry. In addition to the speed settings, the "stroke" of the device is adjustable.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Here is a photo showing, what I believe, are bite impressions on the right cranium. I am interested in other opinions/interpretations. Please post.

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I'm thinking perhaps I should have posted all of this as posts under a single topic. I apologize if it is difficult to follow in the manner I used.

Thanks to Auspex for consolidating the topics and making it much cleaner.

Edited by snolly50
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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Hey John, looking good! I'll let the experts comment on the bite marks question..unless its from my wife's cat on my arm, I don't know diddly!

Fun project. Regards, Chris

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Hey John, looking good! I'll let the experts comment on the bite marks question..unless its from my wife's cat on my arm, I don't know diddly!

Fun project. Regards, Chris

Hi Chris, thanks for looking. I'm thinking the gouges to the skull are the mark of a saber equipped cat, but that is of course just wild speculation. I hope someone with some experience will offer an opinion. It's almost "bug season" let me know when you see something wild.

Here are a couple more photos as she approaches completion. There is clean-up work to be done throughout. The base of the skull needs additional matrix removal. I just have to decide how much. The other end will need refinement and there is an off chance that an incisor or two may be there. Planned refinement includes "dishing out" the eye sockets. One of the difficulties with this material is the lack of color contrast between fossil and matrix. The "eyes" will show better if I cut the infilling matrix back to produce some shadow. When wet, the fossil remains off white, while the matrix turns a milk chocolate color. So dampening it is helpful in spotting little patches of missed matrix and seeing spots that need more work. I use a damp cloth to avoid saturating the matrix. I don't want it to get water logged and go all gooey.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Nice work Snolly. When you are done will you soak it in a consolidant of some sort and will that bring out the color contrast just like being wet?


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Looking great, Snolly! I've had disasters like yours happen to my fish before- it sucks. But like you said can't make an omelette without breaking some eggs.

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The "bite mark(s)" do look very possible! The way the fossilized bone is fractured, indicates that the fracturing was done before it was buried and fossilized.

Fractures after being exposed are from "expanding matrix" from pressures within and a fossilized skull would break at angles with straight breaks, not like flakes or conchoidal fracturing like you would see on a piece of chert. Yours looks like it was crushed at the time the Oreodont died. The lower jaws being intact are a good indication that is the case. The skull and any connected bones would have been held together by hide and tissues, before burial. Often... like the other Oreodonts sold at the last auction, were dismembered AFTER death in most cases and missing the lower jaws... and then buried for preservation later.

Check for any additional crushed areas, or broken teeth that were found...after the prep work. I doubt if this one would have any rodent gnawing as the lowers are so tightly connected. The other skulls could have rodent gnawing. They look like gnawing you would find on wood or deer antlers found on the ground.

Dr. Kent Sundell of Casper, Wyoming and a geology professor at UW, Casper did some nice work on the burrowing nature of Oreodonts. Complete skeletons with new born Oreodonts all together were the proof he kept encountering in his finds in Wyoming. Kent was exposed to Badland collecting by a member of the Fossil Forum in the 1970's. Great work Kent!

Having a nice fossil is the more entertaining part of the hobby. It is prepping that will be the most frustrating and time consuming part! Done it. Been there. Finding a "naturally" eroded out skull or turtle is for the luckiest collectors. But, with the large number of collectors out, a specimen just has time to be partially weathered out before collected.

Keep posting progress. I always preferred Elmers Glue (the white glue that dries clear) for putting parts back together. The bone will absorb some, let it dry for a few minutes and the parts stick together like magnets!

Edited by Ray Eklund
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Thanks to Scylla, KansasFossilHunter and Ray Eklund for the recent comments. Scylla, I'll go ahead and confess now - I am an acrylic sprayer. Yep, I've been known to spray fossils with clear, matte acrylic. This started with fish plates. When I first started prepping I was advised to do this to avoid the fish "drying out and flaking." Now I know that many oppose this practice. When pressed, these folks usually aver that the acrylic will "yellow." Well that was probably once true. Now the stuff I see says; "anti-yellowing." Bottom line I have fish plates sprayed 25+ years ago. They look great. In 50 years? Who knows, but I like to live dangerously. I do have Vinac, that I used with some dino bone. So that's an option. I am also open to any suggestions. That's why this Forum is so great. It's a chance to be exposed to a host of options/opinions.

Ray, thanks for the comments on the "bites." I have seen Sundell's article on burrowing oreodonts - fascinating. I have also run across the assertion that some were arboreal. I thought that far fetched until I thought of the gray fox we have here. I have seen them high in trees. I've never tried Elmers. I use Duco on stuff that will be under stress (broken slab) and the super stuff for small repairs. I have Elmers, so I'll give it a try.

Thanks again for the comments. I hope to post more of the prep as it moves forward.

Edited by snolly50
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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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As a bonus to the prep experience of this critter, I discovered soon after I received it that the teeth are fluorescent! Last night I attempted to photograph the phenomenon. Nikon D600 with 50mm lens; tripod mounted; f/1.8; exposure .77 seconds; ISO advanced to 1250. The photo was processed with Photoshop Elements 11. It was cropped and the file size greatly reduced for posting. The shot was taken in a totally dark room; the fossil illuminated via a small hand held lamp with a mid-wave UV tube. Unexpectedly, this specimen fluoresces more vigorously under mid-wave, as opposed to short-wave UV.

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The color of the fluorescing teeth is slightly more "greenish yellow" than the photo captures. The dark spots on the mandible are small bits of uncleared matrix. The white spots visible are bits of lint probably from the paper towels. This was a fun exercise. Thanks for looking.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Wow Snolly that sure turned out to be a great project. Thanks for bringing us along.

Predation evidence is fascinating. It sure looks like it would be tough discerning matrix vs. bone

It's hard to remember why you drained the swamp when your surrounded by alligators.

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GREAT JOB SNOLLY!

The fluorescense really makes those teeth stand out!

Thank you for posting this!

The more I learn, I realize the less I know.

:wacko:
 
 

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Gallery for images of Fossil Jewelry, Sculpture & Crafts
 

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...The fluorescense really makes those teeth stand out!...

That's what brushing with Gleem will do for ya'! :P

"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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Gee Snolly. What did your dentist have to say about your latest check up?

I think you need to brush those teeth more often.

This is one thing I noticed on running a SWave ultraviolet in a carton of jaw sections. A light greenish buff fluorescence. Some broken Chadron Member bone had green. But the Brule Member bone had none.

I suspect the teeth are getting some mineral in their Phosphate structure. (I believe teeth enamel is Calcium Phosphate?) The calcite in the area is "orange". The brown chalcedony had none.

Still... it looks pretty weird. Nice photography! I still am working on getting Macro photographs with a Canon... too many buttons.

Edited by Ray Eklund
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Thanks for the comments on the fluorescent teeth. That was a fun photographic project. Next time with UV illumination I'll know to "dust" the subject to get rid of the white glowing dots. And yep, my teeth do glow under UV. It's from all that good fluoride toothpaste I've used over the years.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Here is a prep series of work on the cousin of the current project. I prepped this Merycoidodon culbertsoni circa 1990. The bubble wrap/tape thingie in the last shot was an effort to protect the two attached verts that were exposed. Sorry for the picture quality. These are scans of prints. Again reduced in size/resolution for posting.

The end result of this prep will be revealed when the current M. gracilis is complete. I believe it will be interesting to see them side by side.

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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