Spent about four hours today at the new spot I visited yesterday (see that post here). Didn't come away with as much, and mostly the same from yesterday. I didn't take many pictures, but there were more Terataspis grandis pieces to be had, of which I took a good many. It certainly isn't easy to find the right rock, and even less easy to break them. Hands on learning was also had as a sharp edge of chert went right through my glove and left a deep bleeding gash in my finger. Now I know from direct experience why chert was the material of choice among prehistoric hunters!
So, just one highlight:
Just slightly covered in matrix, and with the impression, the hypostome of a Terataspis. I'll need to do some light repair as two pieces broke off while trying to extract it from a much larger rock. That's what glue is for! It's not very large and impressive for the species -- about the size of a thumbprint; the specimen at the ROM is about 7 cm wide.
I have digital versions of this one, and it is free to download online, too. However, there is something to be said about having a physical copy. It wasn't cheap, but nowhere near for as much as I've seen these go for online. This is the classic green trilobite bible, and in pretty good shape.
It is supposed to rain for the next two days (it is still spring, after all), so any fossil activity will likely be lab prep stuff. Saturday is looking like a sunny stunner, so perhaps another outing. It's been 66 days since my season started, of which I've spent 22 out in the field. In that time I've bagged representatives of 15 trilobites, with at least one undescribed species and a boatload of Terataspis parts.
I felt the need to get out do some collecting today, but not having wheels means I have to keep my trips local for now. London is not known for many things other than my internationally famous cat, and geologically it is post-glacial vomit of sand and erratics several hundred feet deep. That being said, those erratics get sorted and used for all sorts of purposes. Today I visited a spot I had written off five years ago. Upon closer examination with my now more knowledgeable eyes, I bumped into all the Devonian formations up to and including the Dundee, as well as possibly bumping into an Ordovician oddball.
Beds of Leptaena. There were also beds of the common red and white Devonochonetes. This tells me Dundee.
Bits and pieces of Eldredgeops rana and Crassiproetus also says Dundee Fm.
Still on the Dundee kick, here are some wee Coronura aspectans bits.
Appears jet black when opened, but browns when it is exposed to air. It doesn't quite behave like shale, but more like black chert. There were some other segments (not pictured) that looked very much like asaphids.
Just this one rock was mostly sand and purple brachs. That may be an Anchiopsis anchiops impression, so it is possible this is the Oriskany.
Turreted gastropod steinkern, matrix-free Paraspirifer with both valves, a free cheek imprint, and a calcite encrusted nautiloid.
Anchiopsis again, platycerid gastropod, and a bunch of dumpy Anchiopsis.
A Calymene platys pygidium from the Bois Blanc. It may continue into the rock.
The surprise trip-maker was these two Terataspis fragments. What is amazing is they are about a 20-30 minute walk from my house. There were other smaller bits of this species around, but I left them in the field.
So, Bois Blanc, Amherstburg, Lucas, and Dundee formations were represented in this material, of which I only made a six hour surface scan of half the area. A return trip is now a must. I'm not expecting riches, but it is convenient with just enough to keep me interested. And, yes, there were rostroconches, but I didn't take pictures of them... or the crinoidal packstones, the blue cherty corals, the tabulate corals, the zillion other types of brachs and bryozoans, etc.
I can say for certain that I bumped into these trilobites: Anchiopsis anchiops, Crassiproetus crassimarginatus, Pseudodechenella sp. (not pictured), Burtonops cristata (too fragmentary to bother photographing), Coronura aspectans, Eldredgeops rana, Calymene platys, Terataspis grandis. And, possibly that Ordovician oddjob. Of the known, eight species of bugs. Not bad at all.
It's been five days since my last (small) outing. That's the longest trip blank since those days between April 6 and 11. That is something I intend to remedy today with a local visit. But, for now, some loose ends as I continue on my rolling 2020 trilobites of Ontario tour.
Not four bugs, but the same Trypaulites sp. pygidium under four different lighting conditions. This was found out my backyard spot on May 7. There was not much else to be had in the material, but I gave it a go for a number of hours.
A trilobite worker informed me that this is likely a new species of Odontocephalus, and requested I post some photos of the pygidia showing the caudal spine with the prongs or notch. Of course, none of my material has it 100% complete given the nature of this material and the depositional environment. Suggestions to find complete specimens are well intentioned, but it is not as though I've been lazy or leaving such things in the field! Problematizing things further would be the fact that the water level at this location is once again rising, so it will be any number of months before it goes down -- if not until next spring. Still, very neat to have examples of what may be a new species. I have my doubts until it is written up which, if history is any precedent when it comes to Ontario bugs, could be sometime in the next few decades!
As promised, the update is wee. There are some major trip plans being made for the end of this month and into June, including some new sites and serious prospecting work that will see me in more farflung parts of the province. I'm very much hoping to add some Ordovician and Silurian trilobites to this year's tour!
That title would make a great first line for a second chapter of a novel.
I am currently covered in dolomite dust, looking more like a very busy baker. As I was teaching every morning the past week, and the weather has not been the greatest (it is actually snowing at the moment), much of my fossil time is spent indoors tackling my "Terries" -- the bunch of Terataspis grandis parts I found the week before.
There are many challenges. One of my scribe styli snapped, leaving me with only the powerful ME-9100, which is not great for fine detail. The trilobites are in a matrix that has crusty, frosty calcite and dense chert. Never very lovely. I am still stuck using a Paasche for abrasion, which is a bit like trying to score holes in iron with a drinking straw. But persist I must!
Much of my focus of late has been one of the promising glabellas. So far, it has been a bit over 6 hours of very slow progress, partially due to equipment follies, but also due to a morphological problem. You see, the glabella of a Terataspis is almost completely round, and so working from the top down means not knowing which way it is facing, which means not knowing if it continue (and in what direction). The last thing I want to do is just scribe freely and accidentally blast off a lobe
This was the first crack at it a few days ago. It's on a big bloody rock that is challenging to move around in my blast box. I can't risk cutting it down until I've determined the direction of the glabella in the event it continues.
Here is the fruit of three hours' labour + a few beers last night. Some closeups with the Olympus as well again to show microsculpture.
And this is where I am now after three hours this morning. I had a bit of a breakaway moment as I was getting bolder with the clunkier scribe.
I still have a long way to go, but I'll update this as I progress...
Another two hours has revealed a connecting part, which helps a bit in terms of orientation:
And this is where things stand at the moment (Sunday, May 10). I am now certain of its orientation.
Compares well to the cranidium pictured in Ludvigsen.
Spent overnight at the Bois Blanc Formation site with a great field comrade. The focus this time was less on the arenaceous hardground, and more on the hummocky material. Although, to be fair, we were fairly systematic in our sweep. Overall, we made out pretty well, and on at least one register, pretty damn amazing. So, on to the report...
This shows the big difference between the two lithologies. On the left is a giant rugose coral in the hummocky material, and on the right is a tabulate on the arenaceous hardground.
I don't get into the habit of picking up corals, but these were small and interesting enough to find their way into my pocket.
Calymene platys occur occasionally in this material, and usually their only announcement is as an outline on the edge of the rock. In most cases, if you can see the outline, it means much of it is already worn away. The specimen at the bottom does continue into the rock, so there is hope it may be complete, even if there is almost no way of preserving that flaky shell in the process. This material can be tough and sticky at the same time.
A small Burtonops cristata that appears to be complete. I've put it under the scribe briefly, and I haven't got as far to see if the pygidium is there, but the remainder of the thorax appears to be.
And now for what was truly exciting, but may not appear so thrilling in photos. We encountered material where there seemed to be a concentration of Terataspis grandis fragments, suggestive of a moulting ground or tidal sorting. Some rocks were so filled with fragments that it was like they were just layered right on top of each other. Nothing complete, but some good parts, including a glabella.
To most people, these would just look like a big bunch of rocks with a few blackish bits, but throughout and buried in the matrix are the telltale pustular signs of the giant lichid. It will require a good deal of time and patience in the prep lab to get this up to par. The shell is flaky, but there are intervals where they are quite robust and inflated in the matrix. The evidence of them was so ridiculously abundant that we only took the best pieces home. Not many trilobite collectors can say they even have the tiniest fragment of this species, and so we were definitely spoiled. I'll post an update once I can spend some quality time in the lab with these.
UPDATE: Just a preliminary abrasion on this piece, before and after. I'm thinking this is a ventral cranidium (maybe... I have no idea). Other pieces I sampled... wow... They seem to just go on and on in the rock, which means I could get some very nice pieces once all is said and done.
And a few more works in progress:
I managed to spend eight hours at my secret Onondaga spot yesterday. I am starting to lose shoreline as the water levels rise, which is not great in terms of short term collecting as it means only exposing material above the highest watermark which is brutally hard. However, it is good in the long term as it may soften up a few more rocks when they are submerged, making splitting more of a joy when the waters subside again, likely in autumn. But there was still enough material to play with yesterday.
Brachiopods are by far the most abundant fauna in this material. The big, round globular kind leave huge globular divots in the impression side of the bedding plane.
Rostroconch seem to be following me around this year. I still pocket the smaller brachs pictured at the bottom if they are matrix-free and possess both valves.
Here is a monster-conch. 4.5 cm wide, or nearly 2 inches. I was able to free most of it from the matrix. The upper portion comes off like a lid so that one could see the detailed structure inside.
Coronura fragments, and this is not even all of them. Some I even left in the field. It is immensely frustrating to go through so much volume of rock and never find much more than this intact.
Odontocephalus cephalic denticle brims.
This is where the revision part comes in. I've been casually assuming all this time that these were Anchiopsis anchiops. Well, hold on there. These are actually likely to be Odontocephalus pygidia.
More to the point, a morphological comparison of an Anchiopsis I found recently at another location, and on the right the Onondaga material. The main differences include width and terminal caudal spine. The former seems obvious here, but the latter was the source of my error. I had thought the pointy tip of the spine was just too delicate, resulting in getting broken, but each of my Onondaga specimens where the spine is present has this notch in place of a pointed tip. Also, note the relative robust width of the base of the spine in relation to the pygidium. Reexamining all of my assumed Anchiopsis bits leads me to the conclusion that this material does not possess this taxon, but that it is in fact Odontocephalus as the only other match among the synphoriinae that has this notched bottom at the end of a longer spine.
And now for the oddball. Just as I can cross off one species from the list at this location, I can add one more. It was getting late in the day, and my eyes were getting as tired as my hammering arm. I nearly tossed this aside as just another Pseudodechenella pygidium but instinct had me look much closer. It was small, so I took a photo and enlarged it to see the tell-tale nodes and pygidial ribs terminating right at the border. Yes, that is a Mystrocephala. It was in the same rock as all the other usual trilobite suspects, but I don't believe it is reported in this material, relegated as it is to the Amherstburg. This is yet another mystery that underlines the need for more sustained research in Ontario trilobites!
A nice time yesterday to head out and make the 1.5 hour drive to the Bois Blanc Fm spot prospected on April 18. Less than a week later, it was essential to give the site more than a 45 minute once-over. The site itself is a good mix of a lot of Bois Blanc Fm material, including natural outcrops and the stuff ripped out of those that are in nice, tidy piles of about 5 metres high by 10 metres wide, and spanning about 60 metres long. There are also more than one outcrop, and more than one rock pile.
There are roughly two main types of strata.
The first is the wavy, bumpy, lumpy calcareous material that weathers blue-grey like Verulam Fm limestone. This material contains abundant rugose corals (some of them human arm-sized!), crinoids, platycerid gastropods (some of them real monsters), bryozoans, and broken bits of Burtonops. The calcareous stuff is only superficial, as it is just mudflows. In the meat of the rock sandwich is abundant, crystalline chert and quartz.
The second type has arenaceous surfaces that weather to expose a lot of massive coral colonies (tabulate, rugose, pipe, etc.), but underneath which are very fine-grained, mostly blank intervals. Bedding planes, where they exist, do not follow around fossils. IN other words, splitting will more than likely shatter through anything viable. This rock is very tough -- perhaps the toughest on par with Dundee Fm -- and Ludvigsen's statement of it being "perversely" so is accurate. There is no sense bashing into the harder material where the bugs are without having some evidence that something is inside -- a trace hairline, for example. Most of the rocks will split blank or with bits, and is a real time commitment.
What was odd about these rocks was the rarity of brachiopods That is not something I am used to in the Devonian. Also, these intervals had virtually no chert nodules.
If the shell had been complete on this one, it would have come home with me. This is an example of one of those giant platycerid gastropods. In this case, a very long lived one.
This one I did keep, despite missing some shell. All of these are more intact and larger than the ones I find in the Hungry Hollow Member at Arkona.
Plenty of examples of the arenaceous, sandy surfaces. And, not by far, the only or best examples either.
Not much comes out small in the lower Devonian! Anyhow, on to talk about the bugs
Anchiopsis are fairly typical inhabitants of Bois Blanc material, but they were not exactly numerous. In most cases, when they did appear in the calcareous material, there were broken and eroded almost to the point of non-recognition; on the arenaceous surfaces, they would take on the pitted, eroded appearance as seen here. I encountered bits of Burtonops and the impression of a Crassiproetus -- neither species examples I took home.
This one floored me. It is new to the collection: Calymene platys. Sadly, the top of the glabella was sheared off by forces long ago. Still, it is a substantially sized and robust specimen. It is very similar to the Moroccan Flexicalymene ouzregui, and just like Moroccan Devonian material, it is nigh impossible to split this rock without shattering through a bug. I will have to glue the head here, and then prep it a bit.
You can see how robust the bug is at the top of this picture. The skin is missing, but I collected the impression where the skin stuck. That will be a tough prep job.
Have a guess what this is. No, not a gastropod. I'll reveal its identity by the end of this blog post.
Some Calymene partials, and stuff I put in my pocket as the day went on. Those Pleurodictyum at the bottom are quite large!
Now what is this? It comes from the same mystery species as above. It is indeed most of the left genal spine of a Terataspis grandis.
The modified illustration above indicates where it would be placed. This fragment would have belonged to an individual of about 400 mm in length. Hardly the biggest (which would top out around 600 mm), but definitely a find to be proud of. This, and the other fragment, makes two examples in a day.
This has already been an incredible season, and it is still just shy of 50 days in. My checklist of Devonian trilobites is steadily filling out -- and I've still not visited Arkona yet this year. My 2020 goal of laser-focusing on Ontario trilobites has been paying off well. Now that much of the Devonian is "done," what remains are repeat visits to obtain more complete and better specimens, and to go a bit farther afield to prospect some Silurian and Ordovician spots.
I spent four hours Monday at my nearby spot with the Amherstburg and Lucas Fm material, and likely split the last remaining viable rocks in the former that could potentially have bugs. The rest is pretty much stromatoporoidal Lucas Fm trash.
A really sad split. This would have been a fairly good sized Trypaulites sp. pygidium, but it just wasn't worth taking home. And so ends what was once a very productive location. I hoovered it well, draining it of its bugs. There may be some stragglers in some of the harder, more blank material, so it will remain my site of last resort. It lasted for well over 100 visits, and it has been very kind to me in giving up 7 different species of trilobite, 3 of which were new to my collection, and 2 of those being exceptionally rare lichids, and one dalmanitid that has never been reported in Ontario rocks. I never found anything complete, but I came close twice. The Devonian in Ontario is a big tease.
I'm fairly thorough and persistent, and so can say I've emptied two honey holes in my immediate vicinity. But a new one cropped up today. I've been meaning to have a look-see at this very large location for a while. It is certainly filled with layers upon layers of sand alternating with water-worn rock that spans the lower to middle Devonian, interspersed with lots of igneous and metamorphic gumbo. At a depth of about 300-500 feet, it is steady waves of glacial backwash. You'd likely have to dig a mile to hit bedrock in this town.
Devonian formations present include Bois Blanc, Onondaga, Dundee, and even some paper shale filled with Leiorhynchus that you find in the Hungry Hollow Member in Arkona. I started finding pretty sad Eldredgeops rana bits, but that was a sign of more to come. This was only meant to be a quick recon, but this place is massive and takes a while to traverse.
To the highlights, then...
This is the only E. rana I picked up and will show here. Why, because it's a roan red rana, that's why. This appeared in some Dundee material that is just littered with tiny red brachs all the way through, like the rock is infested with fat mites. The same process of mineralization that turned them red seemed to have worked its magic on this pygidium.
This battered bug bit is not even worth focusing the camera on. If, as my field comrade Kevin says, E. rana is the cockroach of the Devonian, Pseudodechenella may be a close contender for that title. Both of these have a very long stratigraphic range. No, I didn't take this one home.
Now this is where I get excited. Dalmanitids. These are not bad at all in terms of preservation, and possibly a bit better than how they come out in the material at my secret Onondaga spot. These both came out of the same rock. In fact, all the following Anchiopsis anchiops were found in it. This was truly a good rock that seemed to be a moulting ground.
The tails come paired with heads. The one on the left is sadly just an impression. The one on the right is likely complete, and I just need to do some cleaning and light scribing to reveal it in full. I've never found a full cephalon of this species before.
More bits and pieces.
No, it is not a fossilized chihuahua head, but an impendent hypostome belonging to Anchiopsis anchiops. This is the better of the two I found. This was a great rock. If I could find a lot more of it, I would be splitting all day.
And what is that pustular bit in the centre? Likely a Coronura bit, so make that species number four at this location.
So that was a nice three hours of exploring. I do plan on going back, of course, and it's nice to add another hot spot to the prospect list. I am hopeful my new backpack comes soon as I'm not sure if my current one will hold up for another adventure. Although my tactical pack is barely a year old, it is torn in a lot of places, and the straps have had to be tied and knotted to other hoops and loops several times. It doesn't help that I carry around about 30 or so pounds of tools in it, and then add another 20 pounds of rock. The thing was bulging at the seams, threatening to burst. Not what you want to have happen in the field, far away from home.
Site knowledge: it's a Devonian buffet. There is no sense in creating a trilobite list associated with the stratigraphy because the rocks are transport erratics from all over.
In other fossil news, I have created a fantastic prospecting field document for Silurian trilobites of Ontario, and am eager to get on the road to trial its effectiveness. Obviously I won't post that here unless my goal was to ensure others would scoop up everything first. But, a few of my field comrades will hopefully benefit.
Tomorrow looks like a rainy, ice-pellety day. A good one to do a bit of prep. On Friday it is back to my secret Bois Blanc spot to do a whole day's work. Stay tuned!
Yesterday was a good day to get out and prospect, what with the nice weather and the fact that the flora hasn't grown in yet (just some budding on the underbrush). So off we went to check on a lead I got back in November, to a spot atop the Niagara escarpment. My maps indicated that the material would be Silurian in age. To my great and utter shame (or from lack of opportunity), I have yet to find any Silurian trilobites in Ontario. That being said, Silurian outcrops represent a narrow band in southwestern Ontario, with much of it being blank evaporites, anhydrites indicative of salt which is mined (yes, we have salt mines -- a perfect place to send one's children!).
The site was an abandoned quarry where the main pit was flooded some many decades ago. The exposures were apparent, and mostly around the fake lake, running the circumference (probably a good 500-750 metres) and a depth from top to waterline of about 3-5 metres. The first thing was to check each interval along the strata. Here is just a small section of the exposed stepped wall:
A lot going on. Some layers were more blocky and massive, others were thin and seemingly calcareous. But whether they were thick or thin, they were almost entirely blank with some tough, dense tiny mineralization when split. It looks a lot more promising than it actually is. Lumpy, muddy, and blank with only a few tiny brachiopods on very rare occasion, and some burrows, and pretty tough to break cleanly. But that is the Silurian for you: plenty of largely blank layers from less than ideal deposition and preservation. There are some layers in the Silurian here that are exceptional; this was not one of them!
From the sensational Silurian! This was my major haul from probing those layers. Muddy little brachs. Well, live and learn! So off we went to do a site-seeing stop.
The Devil's Punchbowl's stratigraphic range, oldest to youngest, would be Queenston Fm (upper Ordovician) to the Lockport Fm (middle Silurian). It's a conservation area, so any excavation would be quite illegal. So, it's a take photos, leave footprints visit.
Here's a nice view of the Lockport Fm that caps much of the escarpment. Both the Ancaster and Gasport Members are shown here. Buried beneath my feet would be the coveted Rochester Fm shale, home of the great Silurian trilobites. Sigh.
There are fossils in it, of course. In the ceiling of a small cavern, a nautiloid impression. Lots of nature to see, and likely a place we'll visit later in the year by hitting the paths. So off we went to hit up one more location before heading home. This time, it was an engagement in younger rocks: the lower Devonian, Bois Blanc Fm.
The photograph washes the colour out a bit, but there is the tell-tale blue chert of the Bois Blanc Fm. We arrived at the area, at which point I got out of the car and did a very quick field scan. It was not the ideal spot to start digging, so we opted to go on a bit farther to find a better outcrop with a different faunal constituency and composition ratio. Prospecting is serious work, well beyond the weekend warrior's penchant for, say, just going to fossil parks and breaking a few small rocks with a mallet!
There are layers in the Bois Blanc that are just choked with corals, forming considerable reef systems and bioherms. The rocks here are not terribly ideal for faunal diversity, and so I'm moving on...
Now here we go. Yes, there will still be corals blocking the view, but these layers are a thinner, blue-grey, highly calcareous shale that splits nice and easy. It has the same colour and consistency as the Verulam Formation, and the similar issue of not always being able to make out the fossils from the matrix when freshly split as opposed to weathered. In the shot above, what appears to be a crinoid head is rolling along with a toppled rugose coral.
Aha! Bingo. There's not much left to the trilobite pygidium here, but I have an eye for trilobitic shell material. Only the margin is preserved here with the underlying coral poking through. This was all the evidence I needed to get cracking into this layer. I knew there would be bugs, but the question remains as to what will result in the best return on investment in each layer?
A much more definitively diagnostic trilobite tail. Just as a refresher, the (work in progress) list of trilobites in the Bois Blanc include the following:
?Dalmanites comis (Hall & Clarke)
? Dalmanites phacoptyx
?[Kettneraspis] callicera [The Acidaspis of Hall & Clarke]
Pseudodechenella sp. aff. clara
Pseudodechenella sp. aff. nodosa
Note that the only phacopidae in the group is Burtonops cristata. There is a species with less microsculpture (Viaphacops pipa) that I need to add to the list here. So, let's settle the difference and call it Burtonops sp. -- At least for now. As a small sidenote, these two species were once Phacops cristata and Phacops pipa (and before that, Phacops cristatus var. pipa). Well, once all the Phacops of eastern North America were taonomically reclassified so that Phacops does not apply here as they do in Morocco, names were changed (for example, Phacops rana = Eldredgeops rana). And so these very, very similar species got split into two genera: Burtonops and Viaphacops. Confused yet?
Another Burt the Bug, this one enrolled and crushed to show the anterior/ventral side. This shale is fragile in spots, which is good to know when it comes to likely preservation (and the need to keep the field kit well-stocked in super glue). That horn-like feature to the left? Not quite sure what it is. I have some ideas that range from the banal to the wishful.
So not a bad outing at all. It began as a failed prospect and turned into something very promising. I only spent 45 minutes at this new spot, and there is a good amount of material to get through. There is some urgency, though: the spot is slated for development and will be buried under houses as soon as construction projects are given the green light to resume. It means I need to hope for the grand trifecta of time, weather, and opportunity to make the most of the spot before it is gone forever.
And this also makes the 40th day of the 2020 season. Out of three slated prospect areas, only one was viable, but batting .333 is not bad at all given that prospecting new sites usually has a success rate of about 1 out of 10. I've also encountered one other site by accident (the Onondaga stuff). So far, I've visited 6 spots total, 4 of which are viable. I haven't even been to Arkona yet this year! This is pretty good given that the borders are shut tight, and it is doubtful that our one last quarry in the Ordovician will be letting us in this spring.
Of course, this is just the first few steps into an adventure that may see me in much longer, sustained periods of prospecting, farther from home. As always, I'll keep this place updated when I can.
Got out for the day to my Onondaga spot. As usual, plenty of rostroconch/brachs/gastros, and no complete trilobites. But, still some neat stuff regardless
A typical haul of non-trilobite items I toss in the bucket.
This rostroconch is huge. It's about 2 inches wide!
A litany of Coronura parts. The last image just hurts. What would have been a full pygidium has been ravaged by the forces of weathering, leaving only the faintest segment outlines.
A fragment of what I suspect to be another Coronura, but I'll need to compare against the images to be fully certain.
The usual assortment of Anchiopsis anchiops. The one on the far right has some fine calcite crystallization.
nIntact cephalons are incredibly and mysteriously scarce in this material. Even isolated glabellas of the dalmanitids seem absent. Here is the positive and negative of a cephalon. Although this picture doesn't make it clear, the right eye is intact with visible lenses. Sadly, there is not enough diagnostic detail to pin down which of the synphoriinae this belongs to.
A nice surprise, making this the fourth synphoriinae, and sixth species overall, to emerge from this material. The high axial ridge and pygidial rib count makes this a dead ringer for Trypaulites sp. The comparative image on the right is from Ludvigsen's classic text wherein he also states this species has not been reported in Ontario, but technically should appear given the shared fauna in the Appalachian basin.
Not the best picture, nor the most thrilling way to end my trip report, but here is what I suspect to be a fairly diminutive (under a centimetre) example of another Trypaulites, making that two in one day. Not as impressive as the first one, and very similar in appearance and preservation as the ones I find in my Amherstburg Formation material (flattened and heavily silicified).
So, overall, not a bad day. I can now report trilobite species number six at this location, if not also ticking off all the available synphoriinae for this strata (very likely Moorehouse Member of the Onondaga).
If I can't find complete trilobites, I can at least draw them. This took a ridiculous amount of time, but I think it turned out well.
Not sure when and what my next update will be. Rain is in the forecast for the next while, and I have some course preparation to get to. If I do get out in the next little while, it may just be to my Amherstburg spot.