Reply To: Case Miller's Original Post

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Jon Cartier

@rleder, @case-miller, @john-christian, @jkallmeyer, @matthew-speights

Black Cat Mountain Trilobite

I had the pleasure of getting to spend some time with the famous Bob Carroll, the sole lease holder of the Black Cat Mountain (BCM) trilobite site near Clarita, OK. His shop is filled with homemade tools and techniques learned over a lifetime of prepping JUST Trilobites from this one Quarry.  He is not just talented. he is a Michaelangelo with Trilobites. He allowed me to ask questions and even capture a bit of video so that I could study and practice working BCM Trilobites. Bob is a very kind and generous guy and I really appreciate his willingness to share some time with me.

I studied what he showed me and practiced on scrap trilobites for 3 years before I was brave enough to show him some of my work. I am still not near what he can do, but I am definitely getting better. Here is a sample of working a BCM Trilobite and my technique.

I start with air scribes to take off the big matrix and expose the outline of the trilobite. Getting too close to the trilobite will cause damage, so the airscribe work must be slow and under magnification. the trilobites are typically one inch or less long.  Stop with the airscribe once the edges are exposed.

Next I move to swivel pin vices and dental picks sharpened on diamond grinding stones. I pick at an exposed side and uncover the entire Trilobite a little at a time. Once it is exposed, I work the landscaping around the base of the trilobite to give it a surface that makes it look living.

After I have the Trilobite exposed and roughly landscaped, I start on the cleaning of the surface. It is challenging to avoid damaging the fine features on the surface of the shell. I have tried several methods, but I do not turn to air abrasives until I absolutely cannot get any more matrix off with the Exacto tip. Under magnification, I pick and chip off as much matrix as I can, working deep into the segments and around the dermal bumps trying to avoid scratching the surface. As soon as I have as much matrix off as possible, I turn to the air abrader. I only hit the surface of the Trilobite in very short passes and check to ensure I am not burning through the shell. You can tell you are burning through the shell when it starts turning lighter color. it is only the width of a few sheets of paper in many areas.  The eyes are especially thin and fragile. be extremely careful here to avoid damage. Also the base of the axial lobe down the center of the thorax is challenging to clean.

Once the trilobite is clean, I finish landscaping and present.

Jon Cartier


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