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."
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...
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.
Recently returned from a three-day dig in New York. Despite all the lovely weather leading up to the trip, an almost wintry weather system was working its way through this part of the world with a lot of cold and precipitation. Not exactly pleasant collecting conditions!
Day 1: Penn Dixie
The excavator had been busy the days leading up to our visit. 160 fresh new piles of Windom shale were dug up and off limits until the annual Dig with the Experts event in May. The excavator did dig up one promising area. One of my field comrades had already visited the day before to start a bench and was finding some good material.
Friday was brutal. We only managed to stay out for three hours given the pouring rain, sleet, and the lake wind. In fact, it was so cold and wet that I didn't really take any site or collector pics.
Despite digging for only three hours, we still managed to find examples of just about every trilobite species reported at the site, missing only Pseudochenella. The two above are Bellacartwrightia sp., Eldredgeops rana, and the bottom two are Greenops barberi and Dipleura dekayi. The Dipleura is exceedingly rare at Penn Dixie, and was found in the Bayview bed.
Day 2: Deep Springs Road
Now an annual tradition, Fossil Forum members congregate at a spot in central New York, a shale outcrop on Deep Springs Road. It was snowing for a bit. Deb sat this one out, but went to Penn Dixie later in the day to find some trilobites.
As I had already hoovered up most of the usual fauna from this site last year with representatives of most of the brachs and bivalves, my sole goal was to find a complete Dipleura dekayi. Sadly, my efforts were for naught after six hours of slabbing and splitting. Most other stuff I found I gave away to other collectors there.
I did find these two phyllocarid carapaces (Rhinocaris columbina) that I gifted to my good friend Tim who had also found an amazing phyllocarid telson.
I didn't do so well on the trilobite front. It was mostly partials for me.
One of the other traditions of this meet-up is that we exchange fossil gifts. Pictured above on the left is a chunk of dinosaur jaw from Tony that could be Triceratops or Edmontosaurus. Top right are two Elrathia kingii from James who just came back from Utah, as well as some belemnites and a gastropod from Jeffrey's giveaway box. For my part I offloaded two bins of fossils to Tony for his museum. At the bottom is a fantastic gift from Tim: a Dipleura dekayi hypostome (very uncommon!) and Piochaspis sellata from the Pioche shales of Nevada.
To my good friend Tim who is a fish fossil fan, my only non-trilobite drawing. Knightia eocaena.
Day 3: Penn Dixie Again
Initially, Jay and I had plans to collect a few hours in Dunkirk where it is rumoured that Dunkleosteus pieces could be found, and a generous offer to go through some Linton coal in search of Pennsylvanian aged fish and amphibians. Things didn't work out that way, and I was kind of itching to find more trilobites at the first spot we were working on the Friday. This time, the dig was not curtailed by weather: it finally got warm and sunny. I spent 12 hours hammering and slabbing.
This is the only site pic I took, and this is a "before" image at 7 am. The chunks of rock in the foreground need to be broken down, and the area around my bucket and pry bar is the bench. By 7 pm, all of that area was cleared out.
As the day progressed, the trilobites were thinning out. I made my last significant find around 3 pm, after which it was mostly coral/brach assemblages in very tough, trashy matrix that would shatter rather than split.
Not much to write home about. This is actually a small haul compared to my usual 50-100 bugs per trip, but the pulse was pinching out and the site's excavated areas may not be ideal for trilobites this year. Still, some interesting pieces to prep.
And speaking of which, I've already thrown one into the lab to give my new tools something gainful to do. The initial field state was only showing the thorax. I used the ME-9100 to remove a lot of the excess rock, the Aro for detailing around the bug, the Paasche for abrasion, and decided to pedestal this. Matrix work was mostly filing and sanding. This kind of matrix preparation is not everyone's cup of tea, but these are common bugs and I wanted to play around with some presentation experiments.
And that's it. Not sure where/when the next trip will be given the sad shrinking of viable or accessible sites in Ontario. But I'll find a way...
This was posted as part of an ongoing thread on The Fossil Forum. I am putting it here for those who are not members of the Forum.
I thought I'd show the steps in how I go about drawing trilobites. I usually begin by sketching one of my bugs from different angles, and experimenting with lighting. Once I hit upon the angle and lighting I like, I get to it.
Here is the simple setup at the dining room table: adjustable neck lamp, the subject, magnifier, an array of pencils, tunes, and water.
At this stage, I've already gone about four hours.
I spend a ratio of 4::1 in terms of putting my eyes on the subject and putting the pencil on the paper. Each area and segment must be treated as unique to ensure some relative degree of realism; to draw what one thinks is there is liable to produce a result that looks... not so real. At the same time, it is important to stop often to check against the entire drawing lest the myopic focus of a slight deviation result in some wide variance later. Using the magnifier, I can check in on the finest details of each crack and bit of microsculpture.
I lay down very faint guidelines once I have the proper scale down. In this instance, the trilobite is not very big, but I want it to fill the page. The pencils are all sharpened at different lengths, which only vary so minutely (and why I use so many at a time). I lay down the more detailed work as I go, working top to bottom so my hand doesn't smudge it.
I use erasers very sparingly, so I need to get it right the first time. No matter how careful I am to remove eraser rubbings, it can make fainter penciling too dark if the pencil tip is going over microscopic grit.
Once the rougher detailing is done, I spend an hour fine tuning and checking against the subject. Another hour or so is spent blending. I don't like the smudging technique to burnish as it is much harder to control, and the result looks a bit, well, smudged. Instead, I use a harder graphite (H to 7H) to try my best to remove or mask more obvious pencil strokes, while also working in the fainter areas and incident lighting. I then use a softer graphite (3B-5B) to darken the shadows a bit, and blend it in with a basic HB.
In this drawing, I've put in all the cracks, mottled areas, and imperfections. This one was in the process of a moult, and so you can make out the little gap from the cranidium and the cheeks, as well as the slight separation between the two last pleurae on the bottom right.
After carefully removing any remaining guide lines with an eraser tip, at 8.5 hours it is complete.
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!
What else can one do that is fossil-related when collecting is not possible and the prep queue is virtually empty? More drawing, of course. Here are the results of a lazy Sunday afternoon (+ Tuesday):
All of these were done using just a standard HB pencil. I wanted to focus on the more "dynamic" trilobite poses as opposed to the straight-on-from-the-top sketch. By drawing these bugs from my collection at different angles and poses, it means relying on more looking at the subject than relying on assumed symmetry. In other words, drawing what one sees, and not what one thinks is there, which is pretty much the standard first lesson of any life drawing class.
Until winter clears, I can foresee doodling up a few more of my bugs. I can't say I mind the practice, and the results generally satisfy me. It isn't preparation, but almost as painstaking.