Over the span of about ten days, I've been able to squeak out some very local prospects, rummaging through river worn glacial erratics at various spots. These are always the source ingredients of mixed Devonian salad, but after a time it is much easier to pick out the formations on the basis of recognizable matrix types. For instance, it is fairly easy to pick out Bois Blanc Fm material since it is, by volume, a whole lot of chert with the appearance of sometimes giant coral that are blue in colour. Whenever I encounter that lithologic type, I get excited as it provides a reprieve from the usual crappier layers of the Dundee Fm with its litany of burrows or brachs. That excitement can easily turn into frustration when one sits down to split, as we are talking about sometimes dense balls of hard chert, the striking of which sends up little flinty missiles that can slash exposed skin. There is a good reason why First Nations made their tools from this kind of stuff! Locked in the chert are fossils, sometimes incredibly diverse and numerous ones, amidst all the horn and tabulate coral. Brachs, gastropods, occasional bryozoans, and of course trilo-parts appear. The one challenge is that, apart from the occasional sandier parts, there are no bedding planes and so this rock fractures where it wants to fracture, generally right through fossils. This means collecting all the pieces, and potentially gluing them back together to be prepared at home... ...And there is no fresher hell than working with solid chert. At times it is like trying to scratch a block of iron with a butter knife. And extra special care is required to move slowly as chert likes to shatter and chip along its own crystal form, at times conchoidally (in mass clumps) or just as partial crystals, and it can take fossil shell with it. With that long preamble out of the way,. 2021 was not so much the year of the Terataspis as it was in 2020 with that one bountiful (now vanished) site. Not even a trace had been found in any of the local erratics across many locations. But, I decided to take a look at some other spots I had either only skirmished or turned my nose up at in the past. Time to perform due diligence in the Devonian, as I may be the only person who spends this much time in it around here! The first stop was about 20 minutes from my home. Finding the right matrix, the trilo-fauna began appearing in fragmentary form (as usual): Pseudodechenella, Crassiproetus, Calymene platys, and the phacopidae (either Burtonops or Viaphacops -- never enough of the specimen left to make that diagnostic distinction). And then appeared the distinct tuberculate and large fragments of Terataspis. Where is it, you might be asking. It's there, and it's buried. Some closeups: Some of the images make it a challenge to see, but this is a pygidium part that continues into the (miserable) rock. At a second spot (also a 20 minute walk from my house), more to be had: Again, issues showing depth and so forth creates a challenge in showing what is here, but this is a pygidial spine with its characteristic branching. I prepared the one piece and eventually glued on the other after reducing the matrix size... None too easy as the Dremel diamond wheel struggled while throwing showers of sparks, so it meant careful work with the angle grinder, and then back in the box for the tedious grind with the ME-9100. I neglected to snap a photo of the single piece that had been worked fairly significantly prior to gluing the top part back on, which has obscured a lot of the work I've done. Without the piece in hand, depth perception issues, lighting, and the usual impediments of photography make this specimen look... hopelessly unclear! In hand, however, it is fairly identifiable. It is simply in that in-between crappy state that occurs to so many prep projects that require glue-downs. The fragment is fairly 3D with branches extending upward at an angle, so a lot of care is needed (and a lot of patience to get through this hard chert!). And then it was back to site #2 for more. This is the ventral shell of the glabella and glabellar furrow. I had to glue it all back together on account of the way these rocks shatter, but it is a substantially sized piece measuring at least 5+ cm wide. Upon zooming in on the furrow, one can see beekite rings. And here be the steinkern. That is one big glabella, and there is more of the fragment in the rock. The question turns on whether or not to glue the ventral shell to the steinkern and prep down. I am thinking it should have at least one or maybe both lobes, but obviously no cheeks.
I did find one other fragment of lesser interest, and even a few very tiny bits I left in the field. I wouldn't say this makes for a photo finish for the season, but as the clock runs out and the temps drop further with snows coming, I can't say this is the worst way to end an otherwise pretty good season with a lot of interesting trilo-surprises. Next post may either be the results of some prep or purchase, or possibly the end of season wrap-up. I saw the first accumulation of snow on Monday. Although it has burned off, another round is expected on Friday. The temperatures look to be nosediving into the proper conditions for snow to arrive and stay, so I will need to make the decision to call the season in the next few days. That just means putting away the field packs and firing up the prep tools, the drawing tools, the next fossil season planning tools. For now, some prep work I performed in the last week. These are not absolutely complete or done, but the bulk of the work is complete. 1. Pliomera fischeri: Initial state. This one is glued in a few spots Halfway mark. Here we can even see the hypostome underneath. This one has got some stickiness with plenty of marine debris vomit. Final stage: Mostly done, but still have some fussy spots to clean up and out. 2. Asaphus expansus robustus. Initial state. This one is missing a pleura, but likely healing damage. Measures about 6 cm. Halfway mark. This is mostly scribe work as abrasion leeches the colour and removes delicate microsculpture. Sadly, there are pitted areas that cannot really be fixed, as those are just the artifacts of preservation. Abrading those areas would only result in making holes and cracks bigger. No matter how careful one can be, mishaps occur. In this case, a piece of the glabella came off with a sticky piece of matrix. I have kept the piece, but it may actually be easier to do a resto. Final stage. Still some fussy gunk to deal with, but the bulk of the work is done. I am just waiting on a shipment of Milliput and acrylic paints to do the resto of the glabellar area. The photos are a bit harsh for both this and the above specimen, and look much better in person. This time around, I spent the time to landscape this in a different way. I began by planing the surface to the bottom edge of the trilobite with the scribe and very light touches of the Dremel diamond wheel, after which point I stippled the entire surface with the scribe tip, lending this the appearance of the trilobite resting on a sandy surface. I also used the diamond wheel to cut the bloc so that it could stand at different orientations. Ok, so not A+ work, which is fine given that I do have some tool limitations at the moment, but certainly a learning experience. I do feel my confidence in working with matrix is improving, giving me a sense of having control over the planning and execution of how the piece should look for presentation as opposed to passively accepting however the matrix might turn out.
And that's it for now! It has been a month of silence on the ol' blog, but behind the scenes I've been doing the frantic end of season squirrel nut gathering thing before winter blankets all possibilities for several months. In October, I was up for a few days in the north of Ontario with two field comrades. Pickings were a bit on the slim side, save for one spectacular never-found-complete-before find that is currently being prepared, and thus not ready for viewing. Suffice it to say, it will be a very tricky prep, and the outcome is far from certain. I've entrusted it to one of the very best preparators, and a specimen like this is worth every penny for getting that level of professional treatment. Since returning from the north, my focus has been local and/or regional. That means a laser-focus on Devonian material. I've been out ten days, across more than eight locations, much of them new prospects (many of those being duds or quickly tapped out). And, with but one exception, all have been pretty much me coming home empty handed. Just yesterday I found a good chunk of Terataspis not far from my house among erratics. Not bad! The prep will be a nightmare, but I have all winter. But, hey, look: a desiccated critter: But if my field pack was empty, at least the mailbox formation was sure not to disappoint: A fairly large asaphid, Isabelina glabrata from the Valongo Fm, Portugal. These typically have a distinctinve feature of presenting with lateral distortion. The smaller trilobite on the lower left is an impression of Placoparia turneminei. Chinese trilobites are still a relatively new frontier for collectors, but ever more research is being done, or translated and released, thus increasing our understanding of some of these locations (such as Yunnan province, or the Chengjiang fauna lagerstatte, which is equivalent to Canada's Burgess shales). This tiny phacopid from Baoshan was going for a good price and needed a new home. Not all Chinese trilobites do I have the confidence to identify. All I can say about this one is that it is Ordovician, and a trinucleid (more than one, in this case) on account of the presence of the pitted anterior cephalic fringe typical of the Order. A good sized Illaenus atavus with the distinctively long and flat pygidium. With a bit of compression/crush damage, it is still complete and a lovely addition to my Russian illaenids. Just when I think that I have all the species under the Russian Asaphus genus, there are always a few missing on account of them being rarer to find, and rarer to be offered. This diminutive (a bit over 3 cm) trilobite is Asaphus broeggeri. This species doesn't get as large as its cousins, with the Klikushin text giving them a top size of 8 cm. One of the many reasons I cherish my Russian connection is that he also digs and prepares material, as opposed to being one of those hustling resellers. He knows I love to do prep, and empathizes with the fossil version of cabin fever of long winters. In my package is this Pliomera fischeri and what may be Asaphus cornutus with healed bite damage on the sixth pleura. This segues nicely into some warm-up prep practice. I'm just getting the tools ready for winter. Pictured above is just a fragment, but it is the pygidium of a Distyrax sp. on account of the terminal pygidial "tuning fork" spine. No, I didn't fuss over every little granule as it is just a fragment. I had picked this up thinking it was different than the more common encrinurid, Rielaspsis cf. elegantula. Although the "fork" was not visible when I collected it, my hunch paid off (there are other telltale signs, including the pygidial axial shape, and the presence of axial nodes that the Rielaspsis do not have). Generally, I have found genal spines of this genus, so it was a treat to find a pygidium. I have a bunch of scrappy, B-grade Ceraurus that I found in Quebec. Always something problematic: missing a genal, an eye, tail spines. I find them to be suitable practice pieces. In this case, although it is missing eyes and tail spines, it has character: note all the brachiopod stowaways. Sometimes they are very flat and thin. Although this one is not finished yet, even more delicate tools may be required to complete this very small specimen without accidentally burning through the shell or blasting off the delicate spines and pleurae. When initially found, only a whisper phantom of a few segments was visible on an otherwise very flaky piece of shale. This one is not finished. It is a puffy one, with both the cephalon and pygidium tucked into the matrix. Some compression/crush damage on the glabella, but it has all the eyes and spines. This one may turn out quite nice! Can't seem to find the original in situ photo, but yet another example of the numerous scrappy specimens I've collected in Quebec. This one is not finished yet, but there appears to be some interesting things going on. The left genal looks like heal damage. The bottom left pygidial spine is simply broken. The left eye was lost to erosion. The pleurae seem to contract in pairs, and the whole trilobite seems to be resting on disarticulated parts of others. Suffice it to say, I have a number of these left to play with. Again, I can't place the original field photo, but this was just the outline of the cephalic fringe. I have yet to find a complete example of Cryptolithus, but I wanted to perform due diligence in preparing the most complete fragments that i do have. Lighting can easily play tricks... This was a complete ventral prep, which takes slightly different techniques. I prepared a few more of them but haven't photographed them yet.
So, I've kept things bottled up for a month, so hopefully worth the wait, and hopefully much more to come. The next post will likely be calling the season, down tools, and a season wrap-up. |
Kane Faucher
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