Help With Green River Fish Fossil

[Tigereagle12345]

I have recently recived a fossil fish (Probably a knightia) from the Green River formation. I am inexperienced with these fossils and have no idea how to prepare them. If someone could give me advice it would be greatly appreciated.

 

The Fossil

 

Outline

 

My tools (The tool on the left is an electric engraver with air scribe tips, I have 2 fine tips and 1 chisel tip)

[snolly50]

Careful with the Dremel on this piece. Cranked up, it will be too aggressive and unfortunately its handling/balance are not great for precision work. I have successfully done several of these fish with low-tech hand tools (including an engraver); but the member that will be most helpful is @Ptychodus04. That is, assuming he is not currently besotted on Texas hot sauce.

[jpc]

I would avoid the dremel completely.  You have some nice dental picks there.  Using thoseand a gentle touch and a ton of patience, you should be able to create a nice fish

[fossilhunter21]

I agree with, @jpc that you should avoid using the dremel. These fish are very fragile and engravers are very destructive. Take your time, and be very gentle. Would love to see your progress on the fish. 

 

Good luck!

 

[Randyw]

I agree with the others. The only time i’ll use a dremel on a grf fish it to remove matrix to get close to the fish then hand tools for the rest. I learned that lessen the hard way….

[Ptychodus04]

9 hours ago, snolly50 said:

Careful with the Dremel on this piece. Cranked up, it will be too aggressive and unfortunately its handling/balance are not great for precision work. I have successfully done several of these fish with low-tech hand tools (including an engraver); but the member that will be most helpful is @Ptychodus04. That is, assuming he is not currently besotted on Texas hot sauce.

Now that I have awoken from my hot sauce induced stupor, I have to completely agree. Your hand tools and a lot of patience are your best route for this fish. Also, you need some magnification. The cheapest route is a magnifying headset. I prepped with one for years when I got started. Naked eye prepping is asking for damaged fossils, especially with these fish. I have prepped large GRF fish with only a needle and the headset. 
 

It will take you a long time, but the results will be much better.

[Tigereagle12345]

Thanks everyone for the advice,

 

I will soon start on preparing it and will post updates as I make progress.

 

Once again, thanks for the advice!

[Ptychodus04]

You can moisten the matrix with a damp sponge to make it a bit softer for easier removal with hand tools.

[MrR]

Please forgive the thread piggyback, but I think the OP may benefit from any advice given on my Green River fish prep. I thought it best to attach my query to the OP's rather than starting a new thread. Yes? If not, moderators have my blessing to remove, etc.

 

I'm working on my first real prep work myself right now. That moistening with sponge trick should come in handy. Any tips that might help the OP and I once we get to the point where things get very delicate? My fish, fairly large Knightia(?), has been sort of a bear to get to this point, but I think I have it on the run. This fish was 2-3mm deep in rather uncooperative matrix, but it looks like it will be worth the hassle. I have been using a very pointed X-acto knife for 95% of it. Should I switch to something else? I have been using a visor style magnifier during prep, FWIW. 4-5 hours into it at this point, FWIW.

 

Oh, and I think that's a bit of  coprolite up above where the tail should be. A piece at the end broke off but I have it to glue back in place once the rest of the prep is complete. Tips from this point on for more intricate cleanup, etc. Thanks.

[Ptychodus04]

This is definitely a Knightia. I like to use a sewing needle in a pin vise for these preps as it provides a great deal of control and pinpoint (pun intended) accuracy.

[MrR]

That moistening trick is a very good thing to know. Had I have known earlier, the prep would have gone a bit easier. I'm at the tail now. Then I'll go back and carefully clean up the spots of sticky matrix here and there. Carefully is the operative word. I got a little too close to some jawbone preservation and a piece broke off. Gah! While it's not really noticeable, I may replace it at the end of the process.

 

Oh, and after it's prepped, is it advisable to brush it with some paraloid, or other such plastic "death preserver"? Thanks again.

[Ptychodus04]

21 hours ago, MrR said:

That moistening trick is a very good thing to know. Had I have known earlier, the prep would have gone a bit easier. I'm at the tail now. Then I'll go back and carefully clean up the spots of sticky matrix here and there. Carefully is the operative word. I got a little too close to some jawbone preservation and a piece broke off. Gah! While it's not really noticeable, I may replace it at the end of the process.

 

Oh, and after it's prepped, is it advisable to brush it with some paraloid, or other such plastic "death preserver"? Thanks again.

You can use a gum eraser to remove the fine layer of matrix that usually doesn’t pop off the fish. Rub gently.

 

With these fish, Paraloid is typically used on an as needed basis. If the fish is flaky, you want to use it. If it’s not, you don’t need it. Otherwise, it’s a preference thing. Some people like the slight darkening that it imparts to the specimen. Be careful not to get it on the matrix as it will darken it as well.

[Randyw]

Thanks for the suggestion! I never thought about using a gum eraser! I’m one who likes to use the paraliod on these fish. I like how it helps make them stand out.

[Tigereagle12345]

Sorry for not posting more recently,

 

I've started scratching at the fossil and I have encountered a dark layer around the fossil. Is this the bones of the fish or just a dark layer? The dark area is only around the section I have scratched at (The edges of the plate, for example, don't seem to have this layer). It would make sense that these are the bones but I remember most other fossils having very distinct bones as opposed to this dark area.

 

Thanks,

Tigereagle12345

 

(Sorry about the somewhat blurry photos, for some reason the focus on my phone that I used to take them isn't working)

 

The fish

 

A close-up of the scratched area.

[Ptychodus04]

You’re seeing the dry season portion of the varve (annual deposit), they alternate between light and dark (rainy/dry seasons) all through the rock. The layers can be extremely thin, so you may not see it on the edge.

 

Judging from the lump in the rock indicating the spine, you have a way to go before you get to the fish. The bone will be a distinctly different texture from the rock. Focus on the spinal area until you get to the fish, then work out from there.

Edited December 7, 2021 by Ptychodus04

[Tigereagle12345]

Now that the holidays are over, I've had time to work some more on the fish fossil. I have uncovered a few vertebrae but unfortunately broke one . Next I plan to uncover the rest of the spine and the tail before attempting to uncover the ribs.

 

Edited January 3, 2022 by Tigereagle12345