Interesting Bug # 1

[Malcolmt]

Let's go on what may turn out to be an extended journey. It is my intention to try to take pictures ever few hours along the way while prepping this little guy. In a few minutes I will post a picture of an unprepared trilobite exactly as found with no preparation whatsoever. What is a bit exciting about this one is that it is actually my bug and eventually when finished I will actually get to keep it for my own collection. Unfortunately for me, most of the really nice bugs and crinoids I prep end up not being mine, but at least I get the chance to experience them and see them come alive in person. I actually have 4 bugs and a nice plate sitting beside me right now that are not mine and waiting for a couple more to be done before packaging off to the owner.

 

To set the scene a piece of matrix a little larger than my fist was split very cleanly into two pieces. The trilobite was cleanly dissected into two pieces across the split as are many trilobites when they are found. I am very hopeful from what I can see that the trilobite will be essentially complete; but that is really only known by the fossil faerie's at this time. You know those little gnomes that during the night hide the fossils for us to find, But they often try to trick us with those pesky partials.

 

  To help you out a little bit I have placed the picture with the trilobite roughly in the correct orientation.

 

Eventually the two halves will be reunited by using a super thin cyanoacrylate that is made for Radio Controlled airplanes. So to answer a prep question that is often asked , Do you glue first then prep or prep then glue. The answer is it depends on the type of split you have, the amount of matrix to be removed and the quality of preservation of the fossil. In about 80% of the fossils I will do some prep first , then glue. I specifically want to see that I do in fact have the correct orientation for the fossil. I am also at this point trying to determine how complete the bug is. You do not want to spend 100 hours on a bug only to discover it is a partial. I once prepped 3 Oklahoma dicranurus for someone and sadly they all turned out to be partials. For example once you determine where the cephalon or pygidium is,  go to where you think the opposite end of the big should be and see if it is there. If you are dealing with a spiny bug like a dicranurus look to see if the free cheeks are there and check that the long pygidial spines are there. If they are not you may be better off investing the 100 plus hours it might take in a better specimen. You will often find partially prepped dicranurus for sale that have been abandoned at the point the preparator discovered that something that should be there is missing. It takes almost as long to prep a dike missing say 1 free cheek as a perfect one, but the price difference between the two bugs when finished could easily be double.

 

It is very important that you know the anatomy of the bug you are prepping. If I am working on a less common bug I will always have a picture of that bug at my prep station . However, reality is that I end up prepping the same 5 types most of the time (eldredgeops, greenops, ceraurus, isotelus, flexicalymene) as this is generally what I and my clients actually find. If it is a spiny bug you must know where the spines are likely to be on your matrix or you will without any doubt destroy them. If the bug is say a phacopid then you are off to clear sailing and can use very different methods to get down to the bug. I for instance on a non spiny trilobite will often use a Dremel with a diamond wheel to quickly remove a lot of the overlying matrix. I would never do this on a spiny trilobite.

 

So without further rambling delay here is the mystery bug prior to any preparation. I am not at this point going to even tell you what the bug is, but if you would like to hazard a guess then  send me a PM and I will let you know if you are correct

 

 

Now here is the same side of the bug after about 15 minutes of preparation. At this point I have not discovered anything that would lead me to believe that the bug will not be complete. Note that you can see black sharpie lines on the left. I always put sharpie lines across the split to make it easy to line them back up when time to reassembly. You cannot see it here but all sides have them 

 

 

If you have anything interesting that you would like to consider having prepped you can always send me a PM and we can discuss.

 

My next plan of attack is to spend about 15 minutes on the opposite side of the split. Following that I will come back to this side and use a Pferd MST31 air scribe with the fine stylus to remove some of the matrix well away from the actual fossil. Note that at this point I already know where the head and tail should be on the fossil and the correct orientation that I am going to prep from.

[RJB]

 You explain things very well.  If only I could do that.   Looking forward to seeing this progress.

 

RB

[FossilDAWG]

This will be a great thread to follow.    

Don

[Tidgy's Dad]

I am really looking forward to this thread developing.

Quite exciting. 

[Malcolmt]

So here is the bug at about 2 hours of prep on this side of the matrix. Until I get the lay of the land so to speak it pays to go slow and under higher magnification . For my primary prep I use an Olympus Stereo zoom scope with a .6 Barlow lens to give a better working distance (the distance between the bottom of the objective lens and the focal point on the fossil). Remember you have to fit your blastbox hand and prep tools into this gap. If you are too high in the blast box and you use air abrasion you will frost the glass on your box pretty quickly. That is why I always recommend a homemade blast box that you make to your specific height and you can change out the glass for under $2.00 as opposed to $50 to $100 on a commercially made blast box.

 

I never ever do any prep except under a scope. You cannot get the precision you need with the naked eye. Your hand is a very precise tool capable of very fine adjustment but you need to see the fine detail to make those moves. That is why vascular and neuro surgeons always use a scope. Most of the time you are trying to remove the matrix at a very oblique angle tangential to the fossil. Never ever blast perpendicular down at the fossil. I am constantly moving the fossil around to get the exact low angle of attack that I need to remove the matrix but not mar the fossil. Whenever possible the abrasive particle stream should go away from the fossil not into it. Hence I am constantly moving the fossil and the abrasive nozzle remains relatively in the same place.  The fossil is placed on a lab jack with a drywall sponge on top of it . This makes it very comfortable to work and I can raise or lower the stage by about 3 inches to get the fossil into prime focus. I rarely ever adjust the microscope itself except for zooming. I used to many years ago use a sandbag but the lab jack is far better. 

 

You can find my rough plans for a blast box here:

 

 BlastBox Page 1.pdf 

 

 BlastBox Page 2.pdf 

 

When I build these now for others I now add 1 inch to the height.

 

So here we have the bug at two hours. I am now getting a much better understanding of the preservation and layout of the bug. We are definitely looking at the cephalon ,edge on with the front going into the matrix. There should be some very nice detail on the bug. I am thinking it will be about average size for this bug.  If you look very very closely you may be able to get an initial glimpse of what eventually will be an eye. Hopefully what looks like four round circles of matrix on the left of the fossil will continue into the other side of the matrix. Other than a bit of scribing on the left side all work at this point has been with previously used 40 micron (sifted to 325 mesh)  dolomite with no additives at 30 PSI using a .015 COMCO nozzle.

 

 

Stay tuned for the next installment later today Hopefully. (Unfortunately leaving now for the dentist)

 

 

[Tidgy's Dad]

 

18 minutes ago, Malcolmt said:

Unfortunately leaving now for the dentist.

Good luck. 

I hope your dentist is as skilled a prepper as you and has an equally steady hand. 

[thebluecatapilla]

Following along 

[DevonianDigger]

[Malcolmt]

1 hour ago, Tidgy's Dad said:

 

Good luck. 

I hope your dentist is as skilled a prepper as you and has an equally steady hand. 

Thanks not a big deal broke out a filling eating pizza last night of all things. 20 minutes in the chair, no freezing... $175.. can't get that doing prep work.... Would love to try some of the dental material someday for trilo restoration using UV light. 

[Malcolmt]

Well we continue to make a little progress on the bug. Here it is at 4 hours at this point I have started using the ARO scribe and I have actually removed a lot of overburden at this point even though it is not obvious from this picture. I know the anatomy of this bug fairly well so I needed to figure out where the eyes wherre and some spines before I could really start to do any serious scribing. I have also  have started to use a number of different size nozzles on the air abrasion. (.15, .025, .030) . I have now determined for certain that both eyes are present and that at least 3 spines continue back into the other side of the split. The spines will likely be a bit tricky as from what I can see the join on them will not be perfect. I suspect a few of you will be starting to recognize this bug already. The preservation on the bug is decent although it seems to start to deteriorate a bit as you move towards the nose of the cephalon. Both eyes have visible facets already. At this point I have not done any consolidation as both the matrix and the bug itself are very solid. I continue to use pure 40 micron dolomite which with quite a bit of patience does abrade away the matrix. Albeit very slowly.

 

[Malcolmt]

Well an hour later at 5 hours prep I think a lot of progress has been made. Starting to get the roughed in shape of the cephalon and a lot of landscapeing has been done below around the bugs cephalon using a CP 9361 scribe on the side of the stylus as opposed to the direct point. Most of the cephalon was covered by about an inch of matrix when we started this process.

 

[Malcolmt]

Jumping quickly in time here it is at 6 hours. I hope a lot more of you have figured out what the bug is at this point. You can see both eyes at this point and just that there is a spine coming out of the eye on the left (also on the right but you cannot see in this pic)The spines unfortunately for me extend into the other side of the split. We will have to see if we can salvage them. Also note the pustules that are starting to become evident on the glabella.

 

[Malcolmt]

Through the magic of the internet here is the final installment for today at 7 hours. I hope that if anything I am showing you how much work goes into a prep of a trilobite. When you see one for sale at what may seem to be an exorbitant price , consider how many hours went into the prep and how many hours were spent finding the bug in the first place. It is hard to see in this pic but I am leaving some matrix at this point around the most delicate areas. Any spines will only have one side cleaned at this point. If I had to make a guess the cephalon is about 50% done at this point and my initial guess is that the bug will take 60 to 80 hours to complete. But that really depends on what we find on the other two parts of the split. 

 

 

[Malcolmt]

Just thought I would show you what the bug looks like when the 3 separate pieces of the matrix are put back together at this point in the prep. Remember virtually all the bugs found from this location are splits that have to be put back together as part of the preparation process. In this case the hammer blow split a rock pretty cleanly into three pieces. I am starting to get a fairly good feeling that this may be an essentially complete bug. I already know that the cephalon and first two pleura are there. this is a very good indicator that the bug will continue into the other side of the split. I see no evidence that the bug continued past the end of the three pieces of matrix.

 

If you look closely you can see the three spines going back into the top matrix on the left. Shortly I will make some cut marks with the indispensable black sharpie on the top two pieces of matrix and use my tile saw to trim down some of the overburden on them. From what I can see of the layout of the bug I will not have too many options in how to do the final presentation. 

 

By the way at this point only one person has PM'd me with a correct guess as to the identity of the bug and where it was found.

 

[Fossil-Hound]

@Malcolmt that is one beautiful trilobite. Thank you for sharing.

[Sjfriend]

Any updates? Just found this thread and want to see how it ends

[RJB]

 My fingers are crossed for you.  Very interesting to say the least!  This just may give me the courage to prep one that I have been putting off for some tiime now.  Thanks man

 

RB

[Malcolmt]

I wish I had an update .... (ah the infamous but) but I got in 18 bugs for other people  to prep(collecting season has begun in other parts of the world) and I have been out to Penn Dixie 3 times myself in the last three weeks so I have not had any free time to work on this bug. I leave for The Penn Dixie dig with the experts on Friday and will be there for 4 days . Hope to meet a few more of you at that event.

 

 I want to get back to this bug  as I do know at this point that the cephalon is pretty much 100% there. The mystery at this point is will the pleura of which I can see cross sections of at least 6 continue into a pygidium. I do not see any evidence of a pygidium exposed at the far end of the matrix so if the bug is there it would be totally within the matrix. Based on the size of the matrix this could be an average size for these. Based on the cephalon I would say it is average to slightly smaller than an average one. When I see these bugs occasionally coming up for sale unprepared they tend to be the smaller sized ones as the bigger ones sell for mucho $$$$ and they are quite a bit easier to prep so the seller keeps the large ones for themselves to prep.

[Ptychodus04]

Isn’t it amazing how quickly your personal projects get kicked to the curb by paying clients? 

[Malcolmt]

Yep...i tend to end up at the back of the line

[Ptychodus04]

4 hours ago, Malcolmt said:

Yep...i tend to end up at the back of the line

I can't even see the front of the line I'm so far back.