On Wednesday, Friday, and Saturday, I managed to get to my nearby site for more challenging rock splitting. On Wednesday, I found a second cephalon example of the lichid Acanthopyge contusa (see the update to my post here). Friday was a bust apart from the usual fauna, taking home only a few common proetid partials and a few unknowns that turned out to be nothing interesting when I got them under the microscope. Today (Saturday) seemed to make up for Friday's failure.
These are the tools that come with me in my backpack. I added the small pry bar today. Some of these rocks are veritable boulders that run deep, and since they are already extremely tough material to break, nothing comes easy. Even when the material doesn't shatter uselessly along a diagonal across the bedding planes, smaller chunks like to split vertically rather than horizontally as the beds can be so thinly packed and dense. Finding the right rock usually comes down to certain external features, but even then those can be blank duds or simply sparsely fossiliferous coral zones. Before committing to any larger rock, I test the edges to see inside first. The tool most often used in my arsenal at this location is the hand sledge.
When I say typical fauna, I mean the litany of fenestellate bryozoans, brachs, and trilobite partials. When I "test" the rock, these are the kinds of layers that usually show the most promise.
I am tentatively going to label this Acanthopyge contusa, although I am not fully certain it might not be another Terataspis as they have similar pygidial morphology. In some aspects, it seems to resemble both, but the preservation is not the greatest on this specimen. Going with the more conservative estimate, that would make Acanthopyge example number three.
Every split requires a careful scan so as not to miss something spectacular. I almost left it thinking it was a compromised brachiopod, but the notch on the bottom made me think it might be a hypostome. And, surely enough, it is a hypostome belonging to Terataspis grandis. Pictured on the right is the illustration by R.P. Whitfield (1897). That makes three examples of this rare lichid, although compared to those found by others and housed in museums, mine are all quite small. This example is barely 1 cm, while the one at the ROM is 7.5 cm. Still, a mini-monster is still a monster!
Sunday update: Spent another five hours out back and I would say these two partial examples of Acanthopyge contusa were the star finds:
Wednesday update: Another three hours as I steadily run out of viable rock. This is one specimen split between both halves of the rock. It is my fourth fragment of a Terataspis, specifically the genal spine. My tally now is two pygidia, a hypostome, and a genal. The likelihood of finding a complete one is along the same odds of winning the lottery, but how many trilobite collectors can lay claim to having even just a single fragment?
I'll be off this weekend to my secret Ordovician location up north, so I hope to post my finds when I return.
I've made a number of return visits to my local spot, but sadly have nothing remarkable to show for it. There is only one type of rock that is both fossiliferous and containing trilobites, and that rock type is a very thin minority at this location. I may have encountered nearly every example of it by now, including boulder-sized ones that make granite seem like butter when it comes to getting into without just creating powder and shards.
So my attention turns to other things, such as creating a kind of an updated master list of trilobites in Ontario. By drawing on the key sources, such as Ludvigsen and Isotalo (among others), this forms a basis for creating such a list. Formation names and taxonomic classification changes have been reflected in creating this list. I've added reasonable correlations based on similar strata in the US, both the Michigan and Appalachian basin. Those correlations appear in a separate column, and are not included in the Ontario species count until they can be found and confirmed in Ontario rocks.
I've also excluded Hudson Bay and James Bay trilobites on account of a lack of more sustained formal description. The list therefore only includes paleozoic rocks south of the Canadian Shield, or simply "southern Ontario."
I am told that there is some anticipated and ongoing taxonomic revision that may result in having to update this list, but revisions are to be expected anyway.
It should also be noted that more than half of these specimens could be classed as quite rare, or known only as fragments. Finding accessible outcrops remains the perennial problem for trilobite collectors and researchers in Ontario, and so even attempting to perform a reliable volumetric analysis of certain formations is imperiled by a lack of substantive sample size.
But this revised list is a good start which tells us something about the trilobite record here in Ontario. I expect to be updating this master list as new resources come available.
I've spent many days over the last two weeks scouring my new local site. I've pored over the literature and attempted to do a systematic analysis of the fauna in each of the rock types, taking extensive field notes. In terms of finds, not counting the numerous Crassiproetus pygidia and Pseudodechenella pygidia and cheeks, there are more days I go home empty-handed rather than dancing on air.
On the third consecutive day at this site, I managed to locate the right type of rock that is generally highly fossiliferous. This type of rock is in a minority at this site, and I've already split through any of the visible examples, leading me to dig under other large rocks in the hopes of finding more of the "good stuff."
The trilobites almost exclusively appear in rocks that contain large fenestellate bryozoans. The environment was shallow marine reef (owing to the massive presence of reef-builders).
Here is Terataspis grandis fragment number two:
I collected the positive and the impression. It is in pretty rough shape, but any fragment of this elusive lichid will come home with me. So is the matter settled about the strata being Bois Blanc? Hold on. Also in the same rock was this:
The top image is a capture from Rolf Ludvigsen's Fossils of Ontario Part 1: The Trilobites, and it shows a cephalon of the lichid Acanthopyge contusa. The image below is my find. But this is reported in the Amherstburg / Formosa Reef. This was already a bit confusing!
Terataspis is only reported in the Bois Blanc Fm. If this were Bois Blanc material, I have not seen even a trace of Anchiopsis in the large volume of material I've gone through. Acanthopyge is only reported in the Amherstburg, and although volumetrically the abundance of Crassiproetus is indicative of this formation, it is also a poor index given that it prevailed across several strata.
Riddles upon riddles aside, I am happy to welcome my second Terataspis, and a brand new lichid to my collection!
Stay tuned, for there is still a very large source rock for me to break down that weighs in excess of a metric ton. It is where the Terataspis was found. More to come this week, I hope!
Update, Sept 18, 2019
I found a second cephalon example of Acanthopyge contusa:
I am acutely aware that I'm back to work on Thursday, and so I've got just two more digging days left of summer. Tomorrow should see me back at my lower Devonian spot, and then a trip to Arkona the following day.
For now, cleaning up some odds and ends. First up is a quick prep job:
I'm being reunited with the other half of my Penn Dixie material on Wednesday, so there'll be more stuff to prep.
And now on to two drawings:
And that's it for me for now. Unless I have amazing finds in the next few days, my next update should be in the autumn.
So I've returned numerous times to my new spot, but have not had the same level of success as my first two outings. I now have a ludicrous amount of Crassiproetus pygidia, but nothing complete and not even a whisper of another Terataspis. If all this material is indeed Bois Blanc Formation, I do find it curious that I haven't yet encountered even a tiny fragment of the dalmanitid Anchiopsis anchiops, which is fairly abundant in that formation. That may be attributable to the specific paleoenvironment in which these were deposited, just as one may encounter trout in one part of a river, but not in a smaller river nearby.
I've been able to identify six distinct types of rock at the site, with only one of those being trilobite bearing. I'll be giving the spot a bit of a rest for the time being while I focus on other projects (and get back to teaching).
I've two illustrations -- one complete, and the other in process -- that I can reveal in the next while. For now, I want to discuss this:
Seasoned trilobite collectors in Ontario are very familiar with this text, a veritable bible put together by the masterful Rolf Ludvigsen who passed away in December, 2016. He was an intellectual giant, a taskmaster, and an exacting top tier scholar. This book was published in 1979, and a lot has changed in Ontario trilobite knowledge since then: the genus Phacops in North America was reassigned to Eldredgeops, the great Bill Hessin formally described the cheirurid Leviceraurus mammiloides, Lieberman and Kloc reassigned Neometacanthus to Bellacartwrightia jennyae, and even humble amateurs like myself have put in tireless efforts in finding some trilobites that haven't been reported in over a century.
The state of fossil collecting in Ontario is mixed. With more site closures, places getting tapped out, suburban sprawl, areas now under provincial park designation, and other issues all too common in many parts of the world, the halcyon days are certainly over. Of course, the undaunted die-hards like myself will continue trying to locate new spots, to dig deeper and farther in unlikely locations, even if they are small and quickly exhausted.
I do think it is time to honour Ludvigsen's project in revising this text. Of course, that is a matter of expertise, time, and money. There is not a tremendous amount of research interest in such a niche project. That being said, some small and remarkable steps have already been taken. For example, Philip Isotalo's book on Ordovician trilobites of Ontario is exactly the kind of enterprise that we need more of. Bill Hessin's invaluable field guide to southern Ontario fossils has also quickly become a kind of bible for collectors in the GTA and surrounds.
There is still so much more work to do, and sometimes I regret not specializing in this field when I entered university. We still do not have a formal description of the Cobourg Fm Isotelus "mafritzae", which should be a top priority housekeeping item.
I can only do so much on my own given my limitations. I'm not a paleontologist, I do not have access to the granting structure. What I do have is the passion and energy. If someone reached out to me and asked if I wanted to play even a tiny role in revising Ludvigsen's text, I would very much take to it like a duck to water.
So, to that end, I've been combing through the literature to create a kind of "master list" of Devonian bugs in Ontario. There are plenty of known unknowns. There are species that should technically be found here by stratigraphic correlation, but have not been confirmed. I'm providing my list, a work in progress. I've been fortunate (and stubborn enough) to find examples of 15 of the roughly 25 species found in Ontario. If you are a trilobite worker in Ontario reading this, I'm more than willing to put in the work needed to revise the Ludvigsen text. We've already seen the resurrection of another of Rolf's projects courtesy of Fred Sundberg in the form of the rebooted Trilobite Papers.
It is a major ask for a major task, especially when we have yet to even see the second volume of the Treatise! But there are so many tireless trilobite workers out there today whose efforts are on par with the greats of yesteryear, such as Jonathan Adrain, Gerd Geyer, Richard Fortey, Joan Corbacho, Gerald Kloc -- just to name a few.
So here is my list so far. My thanks to the indefatigable efforts of Scott Morrison as the true trilo-lit archivist par excellence for putting key documents in my hand. I hope this list assists our collectors -- professional and avocational.
Pseudodechenella ?rowi / ?arkonensis
Widder (Hungry Hollow)
Eldredgeops iowensis southworthi
Crassiproetus sibleyensis* (corr. Michigan)
Pseudodechenella nodosa* (corr. Ohio)
Odontocephalus selenurus (?)
Coniproetus folliceps (corr. NY)
It's not often that one can find a trove of fossils within one's vicinity-- in my case, within walking distance of my house. So time to spin a yarn and show some pictures.
There's a spot I've been returning to for going on six years now, and it has been pretty good to me in giving up its treasures. Nearly all of its material was trucked in, including rocks from the Bois Blanc, Amherstberg, and Dundee Formations. Of course, it stopped being productive by end of last year, and although it is provided me with fantastic pieces of trilobites such as Anchiopsis anchiops, Mannopgye halli, and Odontocephalus sp., among others, it's pretty much tapped out, with some areas being too overgrown now. Nothing left but splinters, mud, weeds, and dirt.
Still, I tried to give it a few more chances in the case of weathering or new material being trucked in. Nope. I've found nothing of interest there all year, so pretty much stopped going.
Nearby, however, is a different story. My new honey hole is also trucked in material -- too poor to make cement, so it is used as riprap / fill -- and there is a lot of it. Perhaps so much it may take me a very long while to tap it out.
Initially I thought it might be local Dundee Fm, and/or Lucas Fm (Anderdon Member) due to the sandy facies. Now, I think it may actually be Bois Blanc material.
So I've done about two half-days of recon and prospecting to get a handle on the site and material rather than do a systematic all-day dig. This stuff, pending rock type, can be dense, dirty, fragile, brutally hard, blank, or ridiculously fossiliferous. There are massive dome-like corals amidst smaller corals of all kinds, but in some layers bryozoans dominate.
And these are some of the medium sized ones! When I started poking around, I thought to myself that it was just a resigned end-of-visit tapping of a few boring rocks.
And then I started encountering some familiar matrix, but loaded with these rostroconch.
And then a few nautiloid/ammonoids started appearing, too. But the really exciting trip-maker that turned around my whole day, and has rekindled my interest in taking some walks outside my house is this:
Yes, a basically complete (I'll know for sure with prep) Pseudodechenella sp. Not sure of the species just as yet. Finding these, or their byrozoan/coral thicket-mate Crassiproetus, complete is far from common. After finding this proetid, I gawped at it for a good few minutes, shocked by my dumb luck! After, I started finding plenty of pygidia and other fragments. That brings me to the end of day one.
On to day two. I needed to recalibrate my expectations so as not to think full trilobites would be popping out of every rock. I was right: I did not find a full trilobite, but something no less sensational. But here's a tour of some of the other finds first.
A whole lot of sea bed goodness.
Long and branching.
This amounts to a hill of b...ryozoans.
More Crassiproetus pygidia. Not pictured yet is a fairly large one (about the size of a silver dollar for those who remember what those look like).
But enough delay. The find of the day, and perhaps the week, month, or year, would be this unattractive fragment:
Yes, it is a piece of a trilobite pygidium. It looks lichid in its morphology, with the little tubercular surface. It is always a good idea when trying to identify something to assume it belongs to a much more common taxon (it is not as far for expectation to fall!), but in this case I couldn't quite figure this out. I initially thought Acanthopyge but the shape was wrong. I had seen this before, but my brain had entirely negated even the remote possibility it could be... that. No, not among the rarest trilobites in Ontario, certainly not. My thanks to my friend and trilobite expert Scott for not only saying it was possible, but in fact certain: this is a fragment of a Terataspis grandis! They are effectively only known as fragments, so this is an extremely lucky find. It also means I have ever more reason to go back to this spot again, and again, hopefully for a few years to come.
So now comes the game plan for collecting examples of each of the trilobites that occur in this formation. Here is what Ludvigsen (1979) reports, followed by my current collecting status (I've updated the taxonomic names):
Lesperance and Bourque (1971, 1979) seem to list a few more in their "amphigenia zone" such as Coronura aspectans and various other synphoriidae. There is also some ambiguity as to whether Trypaulites calypso and T. erinus may appear, in addition to Odontocephalus selenurus (of which I have a single cephalic fragment). Lesperance and Bourque are, of course, drawing from material in the Gaspe limestone, so correlations with strata in Ontario can be a bit tricky.
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...