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.
Just returned last night from three heavy days of digging at Penn Dixie. My friend Malcolm and I likely cleared about 1500 square feet of area, working sun up to sun down. As Deb had to work, and I don't drive, it meant taking a train to a station en route to the border, with Malcolm picking me up along the way.
Just getting started. A lot of the place has been peeled back, or otherwise under a heavy load of overburden. At this rate of excavation, the trilobite pit is already starting to encroach on the westernmost area near the nature path. As there were no easy benches, we had to create them.
The next morning. As is usual for us crazy canucks, we work steadily in cracking out large slabs for about half the day, and then spend the remainder splitting them. This was what we left from the evening before, and then it was the same process again for almost 12 hours. We encountered a number of challenges. The rock was extremely dense and dry without the benefit of being saturated in water to facilitate bedding plane cracks. This meant our splits would more likely shatter rather than split through along any planes. A few potentially nice bugs were sheared through or shattered on account of the nature of the matrix. Also, cross-bedding made unlocking the slabs more difficult and time consuming, if not also a network of awkward (and sadly blank) domes underneath the layer.
And yet another point on day 2 after removing some slabs for splitting.
Here I am trying to lever out a stubborn slab with a small pry bar, with a pinch point bar to my right to keep the crack wedged open on a secondary slab. Sometimes a loose slab would be connected to adjacent ones, and so requires a bit of persistence and power to lift them all out in one go.
We don't fool around. As members, we can access the site after public hours, and that is when we fire up the rock saw. Here we are scoring relief cuts in the very cross-bedded material.
This nice little prone popped right out of the rock intact. Prones come at a higher premium than the much more common rollers.
Just a small selection of the finds. We didn't do badly, but we've had better results in the past. The nature of the rock and area was a bit on the parsimonious side. And yet we still came away with quite a few trilobites. As I was taking the train back, I could only stow a few pieces (shown here) in my luggage; Malcolm will be passing through in a few weeks with a whole 5 gallon bucket of my finds. There is no doubt I could have come away with three times as much, but I was being far pickier in tossing away stuff that was incomplete or had no chance to be excellent. I'm really just trying to harvest enough prep material for the winter. The number of partials/incompletes we encountered probably number into the thousands.
These two pieces show some promise. The little slab with the three-quarter profile will likely have some crush and distortion damage on its hidden side. The loose prone is missing a bit of pygidium that I can restore with a bit of milliput.
Some other promising candidates that might lend themselves to some fancy prep.
Overall, despite some limitations, our hard work forced the stubborn rocks to give up whatever treasures it had. It's a challenge to sustain that effort over three days, and I can certainly feel the after-effects of it all today. I will try to get back to PD one more time this year just to beef up my winter prep inventory. I likely have another trip or two to Arkona to look forward to, and the autumn Bowmanville trip which will signal the close for the collecting season.
In an effort to turn the collecting season around (which, on balance, hasn't been bad), I managed to get out to Arkona three times in the last seven days, each one with a different field companion (Deb, Malcolm, Greg). We worked the Hungry Hollow Member almost exclusively. Those who have made that 2-4 feet of strata understand how frustrating it can be to work in: generally crumbly, dirty, virtually no bedding planes, and so filled with coral that if you never see horn coral again that would be too soon!
This is generally the kind of stuff one has to go through. It is quite dominated by coral, but there are shaly pockets where crinoids, bryozoans, brachiopods, gastropods, blastoids, and trilobites can be found. However, it is also a bit of a shredder: only the hardiest specimens remained intact in this high energy environment, so bits and pieces are the norm... when you can see them, as this stuff is pretty dirty.
I did stray briefly to the hard encrinal layer that the Hungry Hollow sits on. Again, no bedding planes, but also brutally hard. Most of what can be found will be shattered through, or a steinkern. Perseverance can be rewarding in finding huge brachiopods, and nicely inflated trilobites (I've only ever seen partials in this layer). Pictured above is just an example I left in the field of a very large Eldredgeops rana glabella.
Apologies for the rubbish photo as this hardly does justice to these (particularly the one on the upper right). On one of the days, it was Crassiproetus canadensis city. It seemed I pulled a pygidium every few minutes. Most are in pretty poor shape, which is the norm for Hungry hollow. Again, the complete specimen eluded us, but this was by far the most examples of this species I've ever collected in one trip.
I should state that all of these are pretty much field fresh, and I won't be prepping them for a while as I need to build up my stores for the long winter. But if one looks closely at this plate, there are three Crassiproetus pygidia (two on the upper right, one on the lower left) plus another fragment.
A bit challenging to make out, but near the bottom is another Crassiproetus pygidium that I kept on account of its massive size. Sadly, it's halfway to steinkern.
A first for me in the Hungry Hollow: carbonized wood bits. Having found these as well placoderm bits this year mark two firsts as these are more likely to be found upstairs in the Widder. In the middle is more Spinplatyceras gastropods, and a few more Crassiproetus pygidia at the bottom.
This was from the hard encrinal layer -- a giant Spinplatyceras. Much of the shell is gone, sadly.
When tabulate/colonial coral appears in the Hungry Hollow, they can get up to the size of wagon wheels. I did extract this one as a matter of circumstance, and it is much larger than how it appears here. The other coral piece in the foreground belongs to it. As I already have an example of this monster coral, I left it in the field rather than lug it back.
Other stuff from my Arkona trip bucket. The middle trilobite at the top (Eldredgeops rana) is indeed complete as I can see on the other side of its crushed/folded nature. On its left is a headless rana, and on the right a pygidium of Pseudochenella. On the right of that is a big brach and a coral. Everything else is Spinplatyceras with the heartbreaking exception of the lowest right -- likely a Pseudodechenella with poor preservation and more steinkern than fossil.
This was the tripmaker: the cephalon of an Eldredgeops iowensis southworthi. Of the five reported trilobite species in the Hungry Hollow, this one is the rarest. It is rumoured that less than 100 of them (almost all fragments) have ever been found, and that the holotype is a single cephalon. I do know someone who did find a complete enrolled one. Complete, this one would have measured possibly more than 10 cm long. It can be distinguished from the ordinary Eldredgeops rana by the number of dorso-ventral eye lenses, but more obviously by its excessively tuberculate shell. In other words, far "bumpier" than a rana. This would make the second example of this species I've found in the last five years, with a third one purchased from a fellow collector.
I've put it through about ten minutes of abrasion, and it still needs far more prep. I almost didn't see it, as its initial state was like much of the Hungry Hollow: dirty and uniform in appearance. All I saw was a bit of a bump, which more often than not means yet another coral. But I spied some little dots poking through, which is suggestive of tubercles. I'm glad I took the chance to bring it home!
There may be so little left of summer before work pulls me away, but I do have some trip plans I'm waiting to finalize. This may not be the last post before autumn!
There just hasn't been any time or opportunity to get out collecting in the last while, and summer is winding down. And, without much material to prep, that leaves me taking up the pencils.
This one doesn't look as impressive as my usual output as it has a kind of cartoonish appearance. However, that could also be on account of the lighting. It is always a challenge to photograph pencil drawings. In person, this drawing is a bit darker as opposed to washed out as it appears here.
This took me a ridiculously long time to complete despite the apparent simplicity of the body plan. When drawing darker trilobites, one of the unavoidable issues is how repeated cycles of layering and blending removes the tooth from the page, making any subsequent work nearly impossible.
A Fossil Forum member suggested I give drawing a Tumido a try. Having never drawn a crab before, I thought I'd give it a go. I initially had a Dalmanites limulurus lined up for drawing, but the crab butted in. I still do plan on returning to the trilobites in the next while.
But each one is now a huge time commitment. What used to take two hours now spans 12+ hours over a few days as attention to detail and quality of rendering require a much longer stretch of time. Hopefully the results speak for themselves. Once I finish a drawing, it doesn't go up on a wall or anything -- I just stick in a plastic sleeve and park it in a three ring binder. I am hoping to get them all scanned, printed, and bound once I have a sizeable number of drawings.
But, in all honesty, I really need to get out and break some rock. This collecting season has been pretty light, and I worry I won't have enough material for the winter!!
Last weekend managed to get out with two Fossil Forum friends to Arkona. I dug exclusively in the Hungry Hollow Member in search of my bucket list trilobites -- a full Crassiproetus, Pseudodechenella, and the pustular Eldredgeops iowensis southworthi. Long story short, they are still on my bucket list!
But other more modest finds were had. I went ahead and gave them a preliminary abrasion to clean off the matrix and mud. When these were found in the field, they tend to be difficult to pick out given the wet, muddy nature of the rock. The Hungry Hollow doesn't really part along bedding planes in most spots except in the more crumbly shaly partings. When they dry, it takes cleaning to figure out why you took it home with you in the first place!
Here is a group shot of a few, including two gastropods Spinplatyceras:
A first for me. I have found placoderm pieces above (in the grey shale widder) and below (in the Arkona Formation), but never in the Hungry Hollow Member before.:
I'm not in the habit of taking coral home, but this one had a neat shape. As the Hungry Hollow is sometimes more coral than matrix, one gets kind of sick of coral!
A closeup of the large gastropod. Still needs another round of abrasion, but shows most of the diagnostic details. As they got larger, they tended to lose their spiny protuberances. This one has some remaining stubs. Usually if there are Spinplatyceras, crinoids are never far off as these gastropods tended to attach to the anal opening of crinoids to feed on its waste. Yummy. I've yet to find one of these with a crinoid attached.
This hot mess (at the moment) is likely a Pseudodechenella. Nearly complete, but missing some of its left side. The nature of the matrix and the preservation makes trilobites somewhat fragile. Currently, it sits underneath a hard, crusty layer of stubborn crinoid and bryozoan bits. This will not be the world's fastest prep.
When I found this Crassiproetus pygidium, all that was showing was a hint of brown shell. But, once under abrasion, I was able to reveal it in its entirety. Moulted partials are more the norm in this strata, making finding a complete one ten times harder than finding a complete Greenops upstairs in the grey Widder shale.
With much of this side of the continent baking in high, hot summer, indoor activities seem the rational course of action. I managed to doodle two more (Canadian) bugs into life. These are taking a ridiculous amount of time to complete now as I do fuss over every crack, dimple, and pustule, while trying to make sure they occupy the majority of the page. There's probably about 30 hours of work total on these two:
No fossil collecting plans etched in stone as of now, but I'm hoping to get out somewhere once the mercury dips a bit. Until then, maybe another drawing and some prep at the bench, trying to stay cool.
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.