Not much of an update this time around, but a few odds and sods, as well as some exciting developments I’m not allowed to talk publicly about yet.
In the last week, I prospected a few sites that turned out to be rubbish, went back to one spot that was not very good, and ditto for another spot where the only thing I picked up were ticks. Yes, ticks. One got dug into my arm, and I had to pick off a few others. Fortunately, these were American dog ticks, or wood ticks, so not the Lyme disease carrying black-legged deer ticks. Here is a photo:
I did multiple full body checks and threw all my clothes on high heat in the dryer. That was a creepy-crawly scare I could do without!
I got nothing completed in the prep lab, as my midline tools are just not up to the tasks I need completed, so I have material that needs to be flipped to a preparator friend of mine. But, boy, it will be glorious!
I also received in the mail the classic Moore “Treatise O,” which is 560 pages of trilo-bliss. I have read this and the 1997 revision cover to cover digitally, but it is nice to have and to hold the actual book, which I got for a song.
My ongoing project to create a definitive field guide on Devonian trilobites continues apace. I mostly have the tedious stuff to complete, such as the stratigraphy sections. I will be accumulating images of each of the trilobites from many sources. I should be very clear and forthcoming that this is not “new research” involving new formal descriptions that introduce new species as I am simply not qualified to perform that kind of work. It is more of an aggregation of current and long unrevised knowledge.
There are so many multi-day trips in the works. I am hoping to tuck into the Silurian and Ordovician as the season continues to unfold. I’m 81 days deep into the season and have yet to wander outside of the Devonian, save for some very light poking around the Silurian back in April. I’m looking forward to hosting one of my favourite field comrades for some very daring adventures. I foresee camping, beer, and much hammering as we chew up the many of the back country miles.
For now, I'll leave off with this Anchiopsis anchiops pygidium found in the heart of tick-land. No, I didn't bring it home, but that's an impressive caudal spine:
Spent four hours yesterday at my Bois Blanc location specifically targeting Terataspis. Overall, it was a great day for it -- sunny and warm. In fact, it was the first time this season that I've had to strip down in the field as I was actually sweating, and now bringing water to digs is essential. That weighs one down, but dehydration can impair a good dig.
Let's kick it off with Deb's lovely find. A lot of it is still buried in matrix. The telltale small, rough tubercles are present, which says Terataspis.
A field shot. Likely a portion of the pygidium, thoroughly eroded. The character of these rocks make it a challenge to find nice pieces if one were to rely solely on just surface collecting. The real trick is to investigate breaks in the rock for long lines where their parts are still buried, or to find a small piece showing on the surface that continues under the matrix.
Another in the field eroded piece. It appears to be a a disarticulated series of thoracic segments, but there is some work in the lab to determine if that is the case.
An isolated pygidial spine with the characteristic barbs. There could be more, but doubtful much more. Some time in the lab cleaning it up will say.
What looks like a pitiful, junky rock may actually be covering over a nice piece here. The more obvious component with the tubercles may point to this being a glabella.
More rocks that many people might not even bother noticing. But this is the trick with these rocks: anything that has a chance to be complete will be under a few thin (but tough) layers. Since the whole trilobite is covered in tubercles, any time I see a few tubercles isolated across the surface, that suggest the possibility that it could very well turn out to be impressive.
I suspect this is showing a glabella and a right cheek. With close inspection, one can make out that the tubercles appear at a few places on the surface, again suggesting a much more complete piece underneath the matrix.
These are not small trilobites, so the rocks one brings back will not be small. Be prepared to fill a bucket very fast. In this broken rock, at the top appears to be an outline. Ventral? Eroded?
Here is a lateral view of the break in the rock, the lower piece. Note the jagged line in the middle. That is the continuation of the trilobite. This will likely be a horribly difficult prep where at some point both halves will be glued together after I determine the orientation (ventral or dorsal). The obvious question might be, "why not trim a bit in the field and separate the overlying matrix from that line?" Absolutely not. The nature of this rock does not allow for that kind of easy separation; instead, going that route will just destroy the specimen.
The trick to finding good Terry specimens in this material is to look for traces on the surface and lines on the side, taking home the most promising pieces to be worked on in the lab with a scribe, abrasion, and eons of patience. Given the high percentage of hard chert, splitting these rocks is going to yield virtually nothing but disappointment or heartbreak. Anything good will shatter right through due to the chert that comes apart in jointed blocks and not clean bedding planes.
Do I have a nearly complete specimen in the last big rock? I won't know for a while. Unlike much easier formations and lithologies, one cannot just rely on clean splits or what is obvious. With this material, you have to take chances and bring what may be promising home for further work.
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: