I can hardly believe it is mid-June already, which means I'm at the halfway mark between the end of the winter semester and the beginning of the fall semester. In my post-Bowmanville week, I've dabbled with some prep, and even some illustrations -- although the latter have been all misfires as I'm having challenges drawing a Walliserops.
Firing up the compressor in the lab, I've managed to eat through a few boxes of baking soda. My first engagement was to finish up that placoderm (see the post on that here). Next up was to get back to the trilobite preps. First up was that lovely prone Flexicalymene croneisi I found at Bowmanville.
Here is a before and after. Both eyes and the distinctly granulated preglabellar lip are intact and pristine. Only light scribing in some spots around it, and some dolomite as well. On the bug itself, it was pure baking soda, with occasional baking soda - dolomite mix on tougher spots (5::1 ratio). Specimen measures 3.3 cm tip to tip, and prone examples are considered rare while enrolled ones are relatively abundant. This species only appears in the Hillier Member of the Lindsay/Cobourg Formation. Currently, it sits atop a softball sized block of very hard encrinal stone that cannot be scored and cut using the ME-9100, and so I've purchased an angle grinder for that task so it can sit safely in the display case.
Another before and after, this time of a Flexicalymene senaria traded to me by a good friend. This one had a few issues with post-mortem compaction damage and a very hard brach and bryozoan attachment on the lower right pygidium that could not be removed for fear of tearing off the shell, so I left that largely in place. The crinoid stem runs underneath this one, giving it the appearance of some kind of fuel line. Despite its problems, it's cabinet worthy to me.
There are still more preps to come, but also at least two fossil trips in the coming week. Once the angle grinder arrives, I'll be playing with that to cut down a few bulky items -- it will be far less tedious than having to do that with the scribe!
Next up, an illustration of a friend's Isotelus gigas that we all know as "Kermit."
This is my second blog post today. I took the time to finally complete this placoderm I found in the Widder Formation back in April. I started it not long before I left for Bowmanville, and tidied it all up today. This is likely Protitanichthys sp. (cf. rockportensis), but more research needs to be done on these arthrodires.
This is an in situ photo of the arthrodire -- a completely discombobulated mess. To make matters more fun, it was situated in the iron-hard brachiopod layer, so the only choice for extraction was to use brute force and hopefully be able to collect all the pieces for reconstruction later. Apart from some of the bigger pieces, it is not entirely clear how this critter is oriented.
I had put it aside to deal with trilobite prep, but I knew at some point I'd have to do something with this so it wasn't just sitting and taking up space in the living room. I started assembling some of the bigger pieces; the smaller pieces were going to be a lot of trial and error -- a bit like doing a jigsaw puzzle without the completed image on the box. There is a lot of matrix to remove as can be seen above. These are otherwise thick pieces of bone that made up the head and dorsal shield of this Devonian fish.
At this point, after about ten hours, I've taken to abrading all the little pieces as well (not all pictured here). The matrix was very easy to remove in parts, melting away under baking soda... But some of the matrix was sticky and as hard as iron. Scribing was not an option when the matrix is this close to the bone as there may be pustules hiding underneath that could easily be knocked off with a far too aggressive approach. Slow and steady is required.
Jump ahead another ten hours and it is done. This is pretty much solid bone. It is also of substantial size for the Widder at about 20 cm from the tip to tip, and this is just the posterior median dorsal plate of the trunk shield (the complete placoderm would have been over three feet long). I've glued it down to a piece of black construction paper and will likely clean up around the edges before pasting it down to a harder backing. There are three small pieces orphaned that I can't find a place for, and there is sadly some missing pieces that must have been lost at the site -- but none too shabby under the circumstances of its forced extraction by necessity. I'm somewhat proud of this one.
I haven't got out to collect anywhere nearly enough this season, and we're already cruising into summer. But I have been working steadily at the drawing table and the prep bench. I'm just about done all the more recent fossils in the preparation queue, with mostly tedious stuff left.
Pictured above were some very awkward, crushed Penn Dixie Eldredgeops rana that I took on as a prep challenge. There wasn't much showing initially, but I knew they were complete despite their contorted orientation. This was a very delicate prep as crushed bugs like these are riddled with cracks, and it wouldn't take too much abrasion or even handling to pop off shell. They are very thin, but I'm proud of the effort I took to do these up properly.
This is a closeup of a very wee bug (~1.7 cm). There's still some matrix in the segments to remove, but it is effectively complete.
Given the number of rollers I have on hand, I can take a few more adventurous risks in preparation. I've done quite a few pedestaled rollers already, so in this case I wanted to cut as deeply as I could into the ventral side. In this one, I've exposed the cephalic doublure, and a portion of the hypostome (the rest is tucked under the impacted pygidium). Soon I hope to do a full dorsal-ventral prep.
This is another wee bug (~1.7 cm) with problems that make it more a B-grader, and so ripe for a prep experiment. What is not shown in this top-down image is my attempt to pedestal this one -- a trickier proposition with a smaller prone.
The two images above show the tiny bug's suspended/perched state. I could have been even more daring, but for a first try at cutting under a prone, I'm happy with it.
I was able to spend the day mucking around in the Hungry Hollow Member. Lots of the usual stuff that I won't show here like gastropods (a very large Spinplatyceras), and acres of coral that just gets in the way of this turbid bed. My goal was to find complete examples of the trilobites Pseudodechenella and Crassiproetus. Fragments abound, but in this puree of a depositional environment full specimens are quite prized and rare. Obviously I did not succeed in finding a full one, but the cranidium of a Crassiproetus above is quite massive (~2 cm along the sagittal), which would have made the full one 6-9 cm in length. I cleaned this one up using baking soda abrasion.
And relatively fresh from the sketching table, two relatively common but cherished Ordovician species. I am trying out a few new tricks on achieving some degree of photo-realism with pencils, and I think it is paying off.
My next post will likely be after the weekend biannual trip to Bowmanville as I hunt one of the few remaining locations for decent Ordovician material. Until then...
Now that my replacement stylus has arrived, it's back to the lab. I've got a bit of a backlog of pieces to prep, so I could have worse problems! I prepare my fair share of these bugs, but this one will present some opportunities to try out some new preparation approaches.
This is how I found it in its field fresh state at Penn Dixie. I bucketed it on account of seeing the full roller.
Another WIP is photobombing this one at the top, but after some exploratory scribing, I encountered two more rollers. Sadly, my scribe blasted off a piece of the middle one, but I can do some restoration with Milliput once I'm done. My goal here is not to be as trilobitocentric, but to prep the brachiopod at the top, and the rugose coral below to make it an association piece emblematic of PD fauna.
Who needs acres of bulk matrix? My ME-9100 sails through the stuff. The leftmost bug is pretty much fine as it stands without more bulk matrix removal, so it just needs a good blasting. I'll work to expose the middle bug's cephalon, but have to be careful not to overexpose its pygidium and thorax given its close proximity to the brach and the other bug. Still, I can do some very precise work with the Aro to create a kind of "channel" between them. The rightmost bug has its cephalon matrix-down, so I'll prep this one with its back showing.
Just to give a sense of the levels I'm working, this perspective shows it is not just like a flat slab. I've been carefully exposing more of the bugs as well as the coral and brach. Once that is done, matrix prep, blasting, and final touches. I'll update this as I go. Stay tuned...
Having just finished teaching a week-long course, and with no work currently penciled in the schedule until late June (although that could change), I can dedicate some serious time to fossils. This means collecting, prepping, and drawing.
I'll be prospecting some new possible sites. Once a site has been picked over, tapped out, or shuttered, it's time to do the work of exploration and field survey. That means extending the search and testing the layers (or the heavy work of exposing them). Once that is done, an assessment is made as to the site's productive life-span: is it something that will last several seasons, or something an individual can clear out in a few trips?
Apart from that, I got word that we are a go for a June engagement at one of the last quarries that still lets collectors in, so I'll have that to look forward to.
It's also time to get some prep done. First up is this 80 mm asaphid, but there are a bundle of Penn Dixie bugs to work on as well.
This is where it stands after about six hours. Apart from some sticky calcite on the right cheek, this has been a delight to work on, but having the ME-9100 makes matrix removal much easier. In fact, since I'm waiting for a replacement stylus for my Aro scribe, I did all of this with the ME-9100, and it is great that I can dial down the BPM when I get close to the shell. There's still some work to do, such as removing matrix between a few segments and the base matrix smoothing, but I'm awaiting some scalpels in the mail to do the inter-segment and touch-up work. As an expert Russian preparator told me, never use abrasion: it burns and lightens the skin no matter what medium or PSI; it must be done by hand. That was my error on the last Asaphus lepidurus I prepped.
I was far too busy and tired this week to put pencil to paper, but I have two WIPs, a few sketched concepts, and Deb bought me some black paper so that I can try out drawing white pencil on black background. At this point, I'm pretty much looking at a 20 hour backlog of bugs to doodle.
Update: Managed to get three since Friday.
The last bit is some tidying up of the trilobite catalogue. I recently acquired this piece, which is a Cambrian Hamatolenus sp. from Morocco.
This post is more a stub, and I'll update it when I've rolled up my sleeves for some of the stuff I mentioned above.
Tomorrow we'll be off and away for the first site, Penn Dixie, and then Saturday for a Fossil Forum group dig at Deep Springs Road. The weather promises to be wet, cold, and miserable, but the alternative is to pass up a rare opportunity to get out and collect. There's no sense in having all these new tools and no new material to work on.
In the last few days, I've been able to try out the new tools. The first order of business was to clear up my prep area as it was a bit of a disaster. I was going to get all four of my tools hooked up into the new manifold block, but at the moment I just can't seem to fix a few air leaks... And these fingers are not nimble enough to use the teflon tape very well, and the tube sealant just creates a goopy mess. So for now I'll be swapping out tools using the quick-connect until I can get my hands on something better for the leak issue.
So this is the little corner where the prep magic happens, what I cheekily call my "lab":
The new 20 gallon compressor is great. The bigger tank means it isn't running constantly, which is important as I'll be running the new tools at 110 PSI.
The ME-9100 was the first tool I tried out of the box. Taking a junky Penn Dixie trilobite in shale, the scribe sailed through the matrix easily. I tried it again on some tougher limestone from Bowmanville, and the chips flew. This is a serious tool with some serious power.
The Paleo Aro was next for its trial run. Again, using the same junky bug, it easily (perhaps too easily) chipped off surrounding matrix to reveal the whole bug in five minutes. That same result would have taken me over 30-45 minutes with my old Aro clone. I will have to adjust to the power of this tool and its longer stylus to avoid making mistakes, as I haven't yet mastered the right way to hold this particular tool for ensuring maximum control -- a necessity when doing detailed work around a fossil. After a combined 20 minutes of usage, however, I encountered a problem: it stalled and would not re-engage at all beyond a one or two second "toot." I tapped the housing, oiled the parts, but nothing was quite working, so I got in touch with my master prep friend Kris from Texas to see if he could diagnose the problem. He suggested removing the spring around the stylus base and working it with my fingers, and then to give a bit of oil to the base plate where the second small O-ring sits. And now it works!
Next up to complete this picture will be to either get a new goose-necked lamp, or find a cheap source of circular fluorescent bulbs as the light in the box from the scope's ring light is just not bright enough when working under magnification.
But for now, it's back to packing for the three day trip.
As I posted last time, I received a block containing the trilobite Asaphus lepidurus for me to prepare. Despite the three of this species I've prepared before, this one was by far the toughest due to the nature of the matrix being hard, sticky, and calcitic. It meant very slow scribing, micrometre by micrometre, under high magnification. Of course, I was having plenty of problems with my equipment that added to the aggravation.
This is the block when I got it, and then after an hour and a half of patient scribing with an ARO clone with the not so great factory tip. As thick as the block was (with trilobite at the bottom), I couldn't risk a chisel... So it was the long way down.
Several more hours as I also work the matrix down. The plan is to have the trilobite standing in this orientation, sitting in a depression. The matrix is starting to play tricks with my eyes. At this point, I'm slowly revealing the right pleurae, heading for the axis, and working around the cephalon.
This stuff is sticky, and largely impervious to abrasion even at higher pressures. It took several hours to find the other eye, negotiating very carefully so as not to accidentally scribe it off. Once the pleurae and axis were largely revealed, working that top of the cephalon took eight or so hours on account of extra stickiness. I also didn't want to knock off the diminutive tubercle by mistake.
After the left side pleurae are exposed at their tips, let the long abrasion session begin. I swapped between the Paasche with the 18 gauge dispensing needle (the disposable needles just arrived yesterday just in time) and the pin vise. There were several very stubborn, translucent bits of calcite to slow me down.
I finished it off with some matrix smoothing, and this is the end result. Measuring 80 mm. Despite the limits of my current equipment, and the unholy horror of this matrix, I managed to do some justice to this trilobite, exposed for the first time in 450 million years.
Been a while since I updated the blog, but winter is a slower time on the fossil front. Compared to last winter, even purchases are down as I either have most of the stuff on offer, it's too expensive, or it's not in pristine condition. But I do have a trilobite coming in a few weeks, and one other I received not long ago. This post will be a potpourri of odds and ends. Lots of stuff coming up...
Pictured here is a wee Acastoides sp. from Morocco. It was cheap and very nicely articulated, so I added it to the trilobite family. I've also had a bit more cash in the PayPal account due to selling some surplus trilobites.
I also managed to spend an afternoon adding to my trilobite sketchbook with these two Russian beauties.
It's a rock! No, not just a rock, but a Russian rock, and a Russian rock containing an asaphid I am currently preparing. Due to the nature of the matrix, and my current tools, this is a 100-200 hour job. I'll create a separate post when it's done.
Hobbling my preparation efforts has been a clogged air hose, likely in the built-in moisture trap for my Paasche AECR. One might think a basic air hose with a 1/4" - 1/16" would be a cinch to replace, but three hours of hardware store visits and plenty of time searching the web says otherwise. I finally got my part and am ready to get to the next critical phase in the prep, which involves swapping between scribing and abrading due to the stickiness of the matrix.
And that wasn't the whole of my prep equipment frustrations, either. I had just been talking with my friend Kevin, saying that I've gone over a year without needing a filter on my lines. Well, no sooner than I said that, the scribe starts acting more like a garden hose. So a trip to Princess Auto to fix that, and to locate a replacement hose (see above). I was also having serious air leak issues, and teflon tape for my big clumsy fingers usually results in my exhausting all the blue words I know, so I've gone for thread sealant instead. The filter/desiccant has already made for a much drier scribing experience. Nothing can be more frustrating than doing precision work under the scope while maintaining critical control of the tool than when it sprays water all over the fossil, turning scribing dust into cakey, opaque mud. And also pictured is a resupply of those handy nitrile gloves.
So when is the first dig of 2019? I'm hoping this weekend, weather and opportunity pending. I've got some other trips planned, too. It will be fantastic to get this season rolling and spend time with my favourite field comrades again as we swing hammers as spring clamours!
Snow-free until January 10, and then it clobbered us. More time spent indoors and thinking that it will take a while for this snow accumulation to melt and get the collecting season back into gear. So that leaves prep and postal formation.
This is a return engagement with a bug I started a few months ago. It is a giant for the location (Penn Dixie) that measures over 45 mm from genal to folded over genal. What is not shown in this image is the folded over/under side that took a ridiculous number of hours. I also took the time to level and smooth the matrix -- something I am learning to get better at, and which also takes a lot of time and patience.
A very lovely full prone Scabriscutellum furciferum from Morocco.
The seller was also kind to add an unexpected brachiopod surprise to perk the package.
My 100th trilobite species! Asaphellus fezouataensis from a really nice seller who also threw in a little enrolled phacopid.
Still trying to relearn my old drawing skills that have been neglected for nearly 20 years, a pencil rendering of an Isotelus.
A Greenops widderensis...
And an Eldredgeops rana with all the crush/distortion flaws.
So, for now, that's about it. I'm somewhat running out of trilobites to prep, and only expecting one or two bugs in the mail. I really hope winter won't be too long!
A belated birthday gift, but only by a day. Had the rock cut and away I went to prepare one of Deb's most prized finds.
From the field to the final product.