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...