Kane's Bug Preps

[Kane]

Thanks, Adam!  

Still a ways to go, but after a nap and a coffee I finally connected the deep furrow with the occipital area. The scribe may have a decent tip, but the valley is deep and narrow. 

 

I also heard back from someone who has seen more than the public has of this species, and he does report that there can be these big tubers on the post-cranidial field and the occipital lobe, as there is considerable variation of the prosopon on these big buggers! Of course, variation also means a bit tougher to prep as the item does not look exactly like the picture on the box.  

 

There is a slim chance that maybe one of the buckets of this stuff contains a complete specimen, but only time at the bench will say!

[FossilNerd]

It’s risky business, but I’m glad to see the aluminum oxide, coupled with your prepping skills, is getting the job done. 
 

Even a fragment of these big bugs seems worth the effort to uncover. So cool with all the tubercles and spiny bits. Too bad no one told the chert!  

[Kane]

An update on this as I come ever closer to being done with it. 

 

Much of the day has been focused on the occipital area, with a need to "channel" between the tubers and connect the deep furrow. This has to be done very slowly and carefully as it is effectively scribing a hollow beneath the tubers where there is a hard layer of chert that tends to shatter if you press just a wee bit too much. Careful sections and teasing smaller bits off is required. And even that is no foolproof method as sometimes matrix will break where it wants to break. To avoid catastrophe, I affixed two little strips of duct tape to the tubers.

 

And thankfully I did. A small piece did break, but since the tape held it in place, I just gently lifted it with the broken piece, applied some cyanoacrylate, and the tape's presence allowed me to fit it precisely where it snapped. 

 

 

I swapped out the aluminum oxide for dolomite to focus on surface work. I then swapped that out for baking soda for finer touches. Do excuse the little bits of stubborn dust that I still need to blow out. This is how it looks dorsal side up, with that nice black plasticky shell. nothing quite compares to having it in hand, though.
 

More detail work is needed, of course, but it will look very much like this in the end. The right lobe sadly does not continue. The left lobe upper continues just a wee bit more. Crush damage on the median lobe is on the posterior and anterior ends. There are trace fragments of the genal that would be incomplete and ventral, so I only indicated their presence.

 

 

Fight valiantly as I did with the chert, I was discovering it would not likely get me much farther; given that the median glabella is smashed in on one side, a number of those tubercles are floating suspended over the base of the shell, so my decision was to remove the tubercles to have a "bald" glabella, or leave well enough alone. But the neat thing is, from this angle, you can see the tubers "flying"

 

A closeup of the deep furrow-channel and how it connects to the deep groove between the lobes and the occipital. I spent a good chunk of the day focusing on these areas. The occipital portion is the lowest elevation on these piece, the difference from the top of the glabella to the furrow just shy of an inch. That's deep! Under the scope, it was like the Grand Canyon.  

 

 

Texture shot. What I've always enjoyed about preparing the glabellar furrows on these beasties is the appearance of these little clusters of mineralized gold stars/snowflakes. 

 

In the end, a real shame about it just being a fragment, and the bashed in part of the glabella. Extrapolating from the size of the components here, the original owner was certainly over a foot in length. So soon it is back to the box of parts to get on to the ongoing projects, and new ones.

[piranha]

figures from Hall & Clarke 1888:

 

 

Hall, J., Clarke, J.M. 1888

Palaeontology VII. Containing descriptions and figures of the trilobites and other crustacea of the Oriskany, upper Helderberg, Hamilton, Portage, Chemung and Catskill Groups. Geological Survey of New York, Natural History of New York, Palaeontology, 7:1-236  Hall & Clarke 1888 text   Hall & Clarke 1888 plates

[Kane]

I forgot I had those plates kicking around. 

But this is a fine match for those spinose protuberances. 

[Phevo]

The prep is coming along nicely, this must be the most odd looking trilobite I have seen to date

 

I may have asked this already, but does the matrix contain enough silica to be able to withstand acid treatment? 

 

I have given fossils found in chert an acid bath and filled the mold left by the fossil with silicone afterwards to make a positive cast

 

 

[Kane]

25 minutes ago, Phevo said:

The prep is coming along nicely, this must be the most odd looking trilobite I have seen to date

 

I may have asked this already, but does the matrix contain enough silica to be able to withstand acid treatment? 

 

I have given fossils found in chert an acid bath and filled the mold left by the fossil with silicone afterwards to make a positive cast

 

 

Good question!

unfortunately, the acid would eat through the shell faster than the chert.

It is an oddball bug, and very few people have examples. Fragments are somewhat equivalent to finding T-rex teeth or individual bones.

 

but since the shell is calcium carbonate, what eats chert would eat the shell, too!

[FossilDAWG]

I think his point was to let the acid dissolve the shell, leaving a high fidelity mold in the chert from which you could make a cast in silicone.  It wouldn't work on the specimen you have been prepping as so much chert has been removed, but it might be an interesting experiment on other specimens.

 

Don

[Kane]

13 hours ago, FossilDAWG said:

I think his point was to let the acid dissolve the shell, leaving a high fidelity mold in the chert from which you could make a cast in silicone.  It wouldn't work on the specimen you have been prepping as so much chert has been removed, but it might be an interesting experiment on other specimens.

 

Don

I understand better now, but when so many of these are uniquely scientifically significant, I couldn’t take that risk. No resto included. I can do no modifications. Some of the fragments are destined for museums that do not have examples. Not many do. I probably sit on more fragments than any museum at this point. 
 

in the end, I am trying to produce study pieces, and not pieces that will look nice in my display case.  

[FossilDAWG]

That technique is sometimes used on research material where prepping by matrix removal is impossible or would damage the surface of the fossil.  A high fidelity impression may preserve much more detail than an abraded positive specimen, and it is perfectly acceptable as a type specimen.

 

Don

[Kane]

1 minute ago, FossilDAWG said:

That technique is sometimes used on research material where prepping by matrix removal is impossible or would damage the surface of the fossil.  A high fidelity impression may preserve much more detail than an abraded positive specimen, and it is perfectly acceptable as a type specimen.

 

Don

I wasn’t aware of that! At this point, I would entrust a museum to bring that to term rather than risk wrecking the specimen. I have good equipment, but not top notch like Malcolm. With those limits I can do most bugs well, but this material is beyond even Moroccan material, as our Malcolm would attest! 

[Phevo]

@FossilDAWG beat me to it and explained my intention and the process very well

[RJB]

Holy Cow!   You sure do pick up some very difficult prep jobs.   and your even using aluminum oxide!  

 

RB

[Kane]

2 hours ago, RJB said:

Holy Cow!   You sure do pick up some very difficult prep jobs.   and your even using aluminum oxide!  

 

RB

I think the tougher stuff has a habit of finding me!  Great luck in finding the fossils, terrible luck in encountering the most challenging matrix types. Ha!

[Kane]

Today was a "clean out some of the neglected stuff" day at the bench. 

 

This one appeared a long time ago in this thread, and I had pretty much given it up for the rubbish pile. This bug had just about everything wrong that could happen to a Russian trilobite: sticky calcite, leaching, an exposed area that was missing shell --- AND! -- it had been found in the field broken, so was glued together with some mysterious Russian glue, but in such a way that it wasn't perfectly clamped, and so there was a pocket. It's a lot better now, although nowhere near the other cabinet sitters for this species.

 

Where I gave up:

 

 

And where I picked back up again:

[Kane]

This somewhat eroded one is tougher to make out, but it is weathered Triarthrus rougensis listing on one side with one long genal spine and the throracic spine. It's only a few millimetres long.

[Kane]

This one I call the unicorn because of another fossil bit under its cephalon. I took this photo while it was still damp, so the white-shine is moisture, not lingering matrix. I spent time to get rid of that. 

 

This Gravicalymene sp. was a bit of a mess: broken and glued in the field, slightly disarticulated, and had some kind of fossil vomit-crust adhering to its right side. It also sits on an an almost paper-thin piece of shale, so pretty delicate!

 

 

Close up detail of the fine granules. Those will not preserve if one abrades too high, or with the wrong mix of dolomite and baking soda: 

 

[Kane]

And just for fun, since I had the tools running already, this Cincinnaticrinus with stowaways on its stem (second photo). The ventral Flexi pygidium took about a minute to blast. 

 

[Tidgy's Dad]

Beautiful work, I love the detail on some of those trilobites especially that last one. Those granules are amazing. 

And I rather love the last piece too, for some reason. 

[Ruger9a]

Kane,  You are very quickly becoming a master prepper.  I'm impressed.

[Top Trilo]

Beautiful bugs, I like the first one and the unicorn, they turned out great. I like the other ones two, there's not a bad trilobite, especially under good preps. 

[Kane]

Thanks, gents!  

And, yes, I figured Adam might be slightly fond of the baby brachs.  

[Ptychodus04]

7 hours ago, Kane said:

It's a bit nerve-wracking working on tiny bugs

For many reasons! But, you’re doing a great job. You sure flattened the learning curve on prepping. I was still bludgeoning fossils with hand tools in the time it’s taken you to get to amazing levels!!

[FossilNerd]

My have you been busy! Not a bad lot. Great job! Since most are smaller specimens, did you do them all in one session or multiple? 
 

[Kane]

8 hours ago, Ptychodus04 said:

For many reasons! But, you’re doing a great job. You sure flattened the learning curve on prepping. I was still bludgeoning fossils with hand tools in the time it’s taken you to get to amazing levels!!

Thanks, Kris!  I still have those "early days" preps sitting in flats, a kind of reminder that might become a penance later on to try to fix those tragic mistakes as best I can. There is this one lovely multiple plate that I wrecked with a Dremel (fossils intact, but the matrix has deep gouges everywhere) that I might try to fix. 

8 hours ago, FossilNerd said:

My have you been busy! Not a bad lot. Great job! Since most are smaller specimens, did you do them all in one session or multiple? 
 

A few sessions this week, for a total of 10 hours. All of these were the easier jobs, for sure! I'm just trying to get those out of the way before the missus puts a moratorium on any prep for the holidays, since she hardly wants to spend her festive time off battling dust.