This is a stromatolite that my in-laws have in one of their flower beds and was collected locally (SW Arkansas). The same area produces horseshoe crab fossils, and my wife's recently deceased aunt had an amazing specimen that was "lost" in settling her estate. I'd say this specimen is about 14" in diameter. They recovered this while the excavations for the basement for their home was being carried out, and they tell me there were several more that were smashed in the process. ARRRGGGHHHH!!!!



RS

ETA:
Pole Creek Shale formation (Upper Ordovician) or Bigfork Chert formation (Upper and Middle Ordovician).

The_Piper just clued me into this thread, thanks Piper, and I have some fossil pics to post.

A couple of years ago, my kids and I went out into the desert west of Delta, Utah to hunt for fossils at the U-Dig fossil quarry. We did the half-day (4 hr) dig and scored over a hundred trilobites and one really nice ammonite. the best part is that they have a fossil prep station on-site and clean your best fossils up for you!


Our amateur paleontology crew.


Proud rock hounds.


Elrathia kingi


Part of our haul.

Super cool way to spend the day if you ever get a chance to go. This weekend we went to hunt for vertebrate fossils on the Green River formation's famous 18" layer in Kemmerer, Wyoming.


That's us with fossilzed Diplomystus and Knightia, fishes from the Eocene era. They last saw the light of day 48 million years ago (give or take).

The Fossil Butte National Monument is nearby and we stopped to view their spectacular fossil collection. It's very different from other "dinosaur" museums that have exhibits that cover millions & millions of years and epochs of time. The exhibits at Fossil Butte are of one single ecosystem and all of the organisms shared the earth at the same time.




"Mass kill" of fish from Lake Uinta.


More fauna from Lake Uinta. It's astounding to think that stingrays once swam in the high desert.


Flora from the same time period. It's difficult to see the scale, but the palms fronds are about ten feet high. Massive


My kids with a thirteen foot alligator specimen from the Green River formation.

All in all a great trip. I brought a ton of fossils home, the kids learned a lot about evolution and the history of the earth where we now live. I also found an amazing chunk of petrified wood that still has some bark left on it. I'll post some close-ups of the fish fossils when I have some time.

BTW, does anybody know how to 'prep' fossils if you don't have an air-scribe or abrasive blaster? Are those tools expensive?

RE tools.

Yes, to me those tools are pretty steep.

You can do the same job with VERY careful use of dental picks and explorers.

RS

Well, I have a new-found respect for paleontologists. I finished work early today and picked up some tools to work on the fossils we collected in Wyoming. I purchased a few dental pics and tried to re-create the mini sand blasting tool I saw used before on my trilobite fossils. I purchased THIS at Harbor Freight and used 220 grit Aluminum Oxide media hooked to my air compressor. It turned out to be too powerful, wonderful at removing sandstone and the fish fossil right along with it in one stroke.

So I gave up on the sand blaster and went to work with the dental pics. Slow & tedious don't do it justice. I had magnifying glasses and spent over 2 hours cleaning just one small specimen. I have eyestrain, my neck is killing me and I though heart surgery was bad. Fish fossils must be particularly fragile. If I scraped one millimeter too deep, it took the scale or bone right off the stone. I denuded several areas no matter how slowly I went. Isn't there a 'prep-my-fossil.com?'

Here's the results:





I also found this intricate piece of fossilized wood on a short hike we did. It still has some bark on it.

AlohaChris wrote:Well, I have a new-found respect for paleontologists. I finished work early today and picked up some tools to work on the fossils we collected in Wyoming. I purchased a few dental pics and tried to re-create the mini sand blasting tool I saw used before on my trilobite fossils. I purchased THIS at Harbor Freight and used 220 grit Aluminum Oxide media hooked to my air compressor. It turned out to be too powerful, wonderful at removing sandstone and the fish fossil right along with it in one stroke.

Heh, I worked for over a week on ONE TOOTH from an Ankylosaur, so I know full well what you mean. One of those magnification lights that manicurists use is very handy as one need not hold the glass and can steady both the fossil and the tools.

You are attempting one of the most difficult types of fossils to prepare. The "lithographic" specimens are notorious for their fragility and the fine grained texture of the matrix. When working with tools start much farther away from the fossil than you feel is needed and remove tiny bits in a manner which leaves a "gully" or "trough" around the fossil, and work very gradually inward until removing more matrix will endanger the specimen. When in doubt don't.

Try common baking soda as your blast medium. Sift it prior to use to ensure no lumps that will act as gravel when passing through the blast nozzle. Your abrasive is FAR too aggressive.

Your air supply needs a pressure regulator that will allow you to fine tune the rate of flow.

I also suggest you find some consolidant that will help protect the areas that you want to save. This consolidant must be reversible (able to be removed without damage). Once you have a VERY THIN layer of this consolidant applied you can then cut masks from a resistive material, such as the food warp "Press-n-Seal". The consolidant will act as a barrier so that when the mask is removed tiny bits of the fossil don't come away. I suggest a very highly thinned mix of Butvar (acetone soluble polyvinyl butyral resin) or Vinac (polyvinyl acetate or PVAC) applied to the area you want to protect prior to applying any mask.

AlohaChris wrote:So I gave up on the sand blaster and went to work with the dental pics. Slow & tedious don't do it justice. I had magnifying glasses and spent over 2 hours cleaning just one small specimen. I have eyestrain, my neck is killing me and I though heart surgery was bad. Fish fossils must be particularly fragile. If I scraped one millimeter too deep, it took the scale or bone right off the stone. I denuded several areas no matter how slowly I went. Isn't there a 'prep-my-fossil.com?'

Here's the results:
images snipped...

Yes, your observations are on the money. Take breaks often and remember that this specimen has lasted millions of years, and will always be there waiting after a very long break! Working when tired is a sure way to mess things up quick!

You might contact those commercial preparation folks and ask about pricing, but don't give up your own efforts yet.

If you need specific answers to questions I'll do all I can to help. Be patient and good luck.

RS

Awesome thread.

Just bookmarking

Nice trilobites Chris!
Does anyone have any idea what this could be?

I went this week-end fossil hunting, found some pieces of kallokibotion shell and this lovely thing . I don't know my vertebrates well enough yet and can't wait to get it to a lab.

Areka wrote:Nice trilobites Chris!
Does anyone have any idea what this could be?

I went this week-end fossil hunting, found some pieces of kallokibotion shell and this lovely thing . I don't know my vertebrates well enough yet and can't wait to get it to a lab.

Yes Areka, I do. That's a hunk of some sort of fossilized bone.

Can you tell us where this was found? Did you recover it? Any idea of the age of the deposit that yielded this bone.

RS

Found in Romania (Hațeg Country) known for dwarf species. I believe it was a Maestrichtian (or close) outcrop. I did recover it, in a few segments (it was a bit weathered down, aside from the cracks).

I have some photos with a scale, but they are a bit blurry