It is very near the one year anniversary of my getting back to the pencils after a few decades' hiatus. Of course, my subject is trilobites as I live and breathe them! I've noted a great deal of progress in my technique in the last year, and since I'm in between fossil collecting trips, this short post hopefully underlines the point.
Like night and day. Of course, the one on the left was a fifteen minute quick sketch, and the one I completed today took about fifteen hours. I've learned a lot in the last year, and set up a number of tough challenges in my pursuit to create photo-realistic illustrations. This will make illustration #33 out of my planned 50 before I scan, print, and bind them in a book. Part of the reason I gave up drawing so long ago was because I had stagnated. Life without the prospect of meeting challenges and to be in a constant state of becoming seems empty to me -- and that is something that follows me from drawing, to preparation, to just about all things I do.
And just a tiny update to round out this blog post. A Fossil Forum friend was very kind in sending me a partial Thaleops from the Stewartville Member of the Galena Formation (Southeast Minnesota) for preparation. Here was how she found it in the field:
And this was after a few hours of prep:
I've been working on a few other pieces as of late, most of which are not yet complete (I swap between multiple projects). I still have a few Gravicalymene in my queue, a faded Ceraurus, lots of Penn Dixie rollers, and the list goes on. But for now, something I did manage to complete after about four hours of some sticky/hard matrix between the segments and some crush/crack issues.
Before and after of this Flexicalymene senaria. None too shabby. One of the most challenging aspects of preparing any Flexi is getting the matrix out from those deep glabellar furrows (the nodular areas on the cephalon at top). Also, negotiation around the sometimes delicate eyes and anterior cephalic spathe, but in this case the crush damage to the cephalon meant work there to reveal more of an anterior brim would not reveal more than more matrix. That being said, the spathe is there. Not a bad representative of the species, either, being about 3.5 cm long.
This will be a smorgasbord post, including one drawing, splitting some gifted shale from abroad, and two prospected sites + finds.
First up, my most recent use of the pencils:
Next, a lot of Conausaga shale (Cambrian) from Georgia, USA gifted to me by my forum friend who came to visit. I took him to Arkona, but we didn't come away with much. I did only slightly better on a second visit when my friend Roger made his annual visit to Canada. But here is a few of the bigger chunks from the 5 gallon bucket:
I made a first pass through these to break them down a bit further, leaving some other chunks outside in the bucket to collect rainwater. They split easier when water-logged. Preservation is a bit dodgy in this shale, but the trilobites are numerous, dominated by Aphelaspis brachyphasis. Here is a shot of an interesting deposition littered with a few trilobites:
A collection of pieces with confirmed trilobites:
Closeups of a few of the trilobites themselves:
My first stop in prospecting for new Ordovician sites was in search of the Whitby Fm shales. Viable Ordovician spots are few and far between as access is restricted given that only one quarry in Ontario permits us biannual visits, development, private property, or provincially protected parks that forbid collecting. This means we are having to fall back on prospecting for new sites, many of which are quite small and require more work to reveal. The pocket I was working was so tiny that it was exhausted in half an hour. Here is some assemblages of Pseudogygites latimarginatus moults. Sadly, nothing complete, but complete ones are rare.
I did take home this chunk for further splitting:
Site number two involved the highly diverse and fossiliferous Verulam Fm. Outcrops of this formation only occur in some creeks, and in quarries. For us trilobite hunters, the Verulam and Bobcaygeon Fms have the most diversity of any formation in Ontario. For obvious reasons of not wanting to see the site plundered by over-collecting, I am not posting any location details -- not even pictures of the strata! We have to take extra care these days given the paucity of productive sites. Here is some typical litter:
All layers were largely dominated by Isotelus gigas, with some examples of other trilobites in the mix. The Isotelus usually appear as fragments, some of which would have belonged to 30+cm individuals if complete. But I'll save the best (trilobites) for last. First up are some typical shell bed hash plates from the uppermost part of the layers. All of the layers contain gastropods, brachiopods, some crinoids, trilobites, and nautiloids. Bryozoans were noticeably absent from most layers.
A weathered nautiloid displaying calcite-filled siphuncle:
I tend to pocket the gastropod steinkerns, mostly of the Fusispira sp. Here is an assortment of steinkerns (gastropods and a few nautiloids near the bottom right) and three brachiopods (Rhynchotrema?).
Let's get to some trilobites. Incomplete ventral examples of Ceraurus and a juvenile Isotelus sporting the long genal spines.
Heads up. One fairly large Flexicalymene senaria cephalon (over an inch wide) buried in matrix, and a juvenile Isotelus gigas.
On the left is a half complete Isotelus from the shell bed layer. Finding them even this intact within such a sifted, turbid zone is uncommon. On the right is the fine specimen Deb found with an exquisitely preserved left eye. The eyes are the most vulnerable area on these bugs, prone to easy breakage. I'll be able to prep this nicely, even if it is not fully complete.
My trip-maker is this 3ish inch semi-enrolled Isotelus. Both eyes are missing, and some parts of the shell are missing, too. The prep is going to have to be delicate as cracks tend to run all through the fossil, and the skin -- although thick -- is very flaky.
I spent about 4.5 hours at this site and only managed to examine about a quarter of it. This was not an all-out excavation visit, but an exploratory scouting mission to track the layers themselves to better guide future visits. For me this is very exciting as it is getting very hard to find viable locations in the Ordovician of Ontario. I hope to get back there again this summer. But it is back to the Devonian for me with two other potential sites to prospect next weekend.
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.
Recently returned from the biannual quarry trip in Bowmanville, Ontario. Overall, I didn’t do too badly, but I also didn’t come away with the great spoils one dreams of finding either. Traditionally, the trips take place in May and October, but a change in management shifted the spring visit schedule, and so early June was our date. The new quarry manager is fantastic and shows a keen interest in what we get up to. Just as long as everyone abides by safety protocols, we will continue to benefit from this incredible arrangement.
Here is our wrecking crew:
Someone in our crew made one of the most significant finds at this quarry. Sadly, that someone wasn’t me! But do have a look at this phenomenal mass mortality slab of 20+ Ceraurus — zoom in and count them. This is going to look amazing once it is fully prepared.
Another of our crew found this massive, eye-watering nautiloid:
My own finds were fairly modest. As the quarry was operating, we had some restrictions on where we could go, and so much of the day was spent on level 4. There are six levels in this vast quarry. The rock in the bottom five is Cobourg/Lindsay and Verulam Formations, and pretty hard. Isotelus bits dominate, while full specimens are a bit harder to find. There are over 20 species of trilobite in the Hillier Member, but most of them are rare. The more common trilobites are Isotelus “mafritzae”, Flexicalymene croneisi, Ceraurus sp.
My trip-maker was this Flexicalymene croneisi. As they more commonly come out as rollers, finding a prone example is certainly good luck. This was in a block the size of a small car. I chiseled out the layer, but the rock was still a good 150 pounds and I am grateful to one of our collectors for taking the time to saw it down for me.
Isotelus pieces could sometimes be quite large. Here is a busted pygidium with my one inch chisel end to indicate scale. A complete specimen of one of these would be a museum piece, for sure.
Other partials of note. I keep these for trades:
Isotelus juveniles. The one may or may not be complete in the rock, and the other is nicely inflated although missing some shell from blast or weathering damage. The latter was found just sitting in a bit of mud.
Plenty of gastropod steinkerns to be found, too:
Didn't come away with any complete Ceraurus, but I held on to these partials:
Not quite sure about this one yet. It might be a Bumastus, but it will need to get some treatment in my lab to be sure.
Even if I had gone away without finding anything, I still would not have left empty-handed. A trade with a good collecting friend of mine means I’ll have some fun preps in my future. First up is a pair of Flexicalymene senaria prones from Brechin, Ontario:
A buried Ceraurus from Brechin. The right pygidial spine may or may not be there:
A complete and enrolled Calyptaulax, also from Brechin.
Two prone Gravicalymene from the Montreal area. A new species for me.
No prep required on this one -- positive and negative impression of Aulacopleura konincki from the Czech Republic.
Overall, not my greatest outing, but also not a skunked one either. It is a lot about luck here, and dividing the time trying to cover a lot of ground searching the blast piles and splitting. Scrambling over those piles is not easy as you want to ensure good footing — not always easy on very irregular surfaces, some of which can be a bit treacherous. It’s not the easiest material to work with, but rarely is anything good easy — it is likely the first rule of advanced fossil collecting and preparation!
I'm chomping at the bit to get to preparation of some of these finds, but it will have to wait until I'm done my current task on a large placoderm bone/trunk shield.
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...
Although it is fossil season, I've not managed to get out much lately beyond some rummaging in the Hungry Hollow Member. Instead, I've been busy with prep and drawing. I'm not quite ready to show the prep just as yet, but I've got some new trilo-doodles. Next trip will likely be Bowmanville in June.
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.
In the last month I made an investment in a new camera. Previously, all my pictures have been using my iPad. The iPad is not an awful photo-taking device, but it does have its limitations when taking macros, and any of the add-on apps like Camera+ only make a small difference in quality. There are very small trilobites or details thereof that could really use a more effective camera.
And so I am now the proud owner of an Olympus TG-5. I won't list all the neat features as that can easily be Googled, but it also very conveniently doubles as a great and rugged field camera. The other feature, relevant to fossils, is its micro/macro functionality. The micro has an in-built photo-stacking feature to resolve issues of depth of field (the closer one zooms on an object, the more radial blur occurs -- something stacking fixes). When I take a very close-up image using the stacking, the camera takes multiple shots at slightly different angles and depths, and flattens the crispest aspects into one image. So I took it out for a bit of a trial run on some trilobites:
Nice, crisp closeups. Just to give a sense of scale, the agnostids in the second picture are only a few millimetres long. Next are two images of the same trilobite (Eldredgeops rana) at different zoom levels:
Overall, much better than using the iPad. The camera was not cheap, but I'm quite pleased that it will be able to serve a useful function for more than just once a year when I'm in Jamaica.