This is my second blog post today. I took the time to finally complete this placoderm I found in the Widder Formation back in April. I started it not long before I left for Bowmanville, and tidied it all up today. This is likely Protitanichthys sp. (cf. rockportensis), but more research needs to be done on these arthrodires.
This is an in situ photo of the arthrodire -- a completely discombobulated mess. To make matters more fun, it was situated in the iron-hard brachiopod layer, so the only choice for extraction was to use brute force and hopefully be able to collect all the pieces for reconstruction later. Apart from some of the bigger pieces, it is not entirely clear how this critter is oriented.
I had put it aside to deal with trilobite prep, but I knew at some point I'd have to do something with this so it wasn't just sitting and taking up space in the living room. I started assembling some of the bigger pieces; the smaller pieces were going to be a lot of trial and error -- a bit like doing a jigsaw puzzle without the completed image on the box. There is a lot of matrix to remove as can be seen above. These are otherwise thick pieces of bone that made up the head and dorsal shield of this Devonian fish.
At this point, after about ten hours, I've taken to abrading all the little pieces as well (not all pictured here). The matrix was very easy to remove in parts, melting away under baking soda... But some of the matrix was sticky and as hard as iron. Scribing was not an option when the matrix is this close to the bone as there may be pustules hiding underneath that could easily be knocked off with a far too aggressive approach. Slow and steady is required.
Jump ahead another ten hours and it is done. This is pretty much solid bone. It is also of substantial size for the Widder at about 20 cm from the tip to tip, and this is just the posterior median dorsal plate of the trunk shield (the complete placoderm would have been over three feet long). I've glued it down to a piece of black construction paper and will likely clean up around the edges before pasting it down to a harder backing. There are three small pieces orphaned that I can't find a place for, and there is sadly some missing pieces that must have been lost at the site -- but none too shabby under the circumstances of its forced extraction by necessity. I'm somewhat proud of this one.
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...
Before my teaching duties resume tomorrow, I was able to squeeze a few more preps in the last couple of days. Nothing significant, but certainly learning moments for me as I better refine my nascent skills.
Already, I can count a few preparation bouts that turned out fairly well: an Illaenus sinuatus, Asaphus lepidurus, Flexicalymene croneisi, and the Flexicalymene senaria / Fusispira nobilis association. So far, so good, and it seems the normal state of things is to be covered in a fine coating of dolomite!
I probed other finds as well to see if there were other things there, and even popped out a headless Thaleops sp. from Bowmanville. Working with sometimes less than ideal equipment can be its own challenge, but I manage. There are still inefficiencies in my preparation "style" whereby it will take me twice or three times as long to complete a specimen than it would a more seasoned professional preparator with a wider array of tools.
So my task queue has been shortening, but by no means at the point where the lab will be going idle for the rest of winter. My next task was to "fill in a gap" in my "prepertoire": restoration. My first attempt was a mixed result on an Isotelus "mafritzae" back in November that has since been finished but I have been remiss in posting said result. This second attempt would be making use of Milliput again, but on a smaller and more expendable trilobite, the commonly found Eldredgeops rana from Penn Dixie. I've got loads of these in just about every orientation.
This bug was never going to make the cover of Trilobite Vogue. It is twisted with tons of crush damage to the glabella and the right side. For added "character," it is also missing a lot of shell. For preparators, this would be the kind of example one would find in a box of rejects to be harvested for parts.
At this point, a bit of scribing around and blasting followed by applying a good glob of Milliput. Some carving and let to cure for a day.
And the last two stages of the process. If you're wondering, the genal area of the cephalon is largely tucked underneath at an angle (super fun to prep - not!). As far as a clean restoration attempt, it is a pretty obvious attempt (but in certain lighting conditions it is a bit tougher to tell). In my weak defense, I don't have tiny tools or tiny fingers to do this kind of detail work. What this needs is a a pin-sized sander to grind and smooth down the transition between the restored area and the original shell. The pygidium itself is a real mess. But, hey, this was already consigned to the chuck-it bucket anyway, so may as well take the opportunity to practice on a piece that I could royally botch.
An incomplete Leviceraurus mammilloides that Deb found in October in Bowmanville. I may have screwed up in an earlier scribing attempt, not figuring that the tail spines would be sitting on top of the bug's plane, so all but the stubs vanished. It was already missing the left genal and part of the right genal, as well as the right eye that I could not save from the impression side, sadly. But it looks a lot crisper now that I've taken the matrix down on all sides and cleared up some of the inter-pleural gunk on this "zipper bug."
While I had the compressor running, why not do a quick blast of this long-tipped Mucrospirifer thedforensis? They clean up fairly easily, but are usually just a waste of dolomite and time.
And these are teed up for their time at the bench: four enrolled Greenops widderensis (one almost completely pyritized) that will be no picnic to prep. The goal with these will be to expose the other side and have them appear as if "draped" over the rock. These are incredibly delicate and flaky, so having at least four on hand to get it right is a good thing as I anticipate at least a few catastrophes with these ones!
On a grey, snowy day, Deb and I paid a visit to the annual London Rock and Mineral show. Shows like these are heavily dominated by vendors who specialize in minerals, jewellery, healing crystals, etc., but there are tables with other stuff as well, including space rocks, microscopic crystallization displays, the local rock club, and the local university's earth sciences department. Vendors specializing solely in fossils were uncommon, and one could encounter a few fossils among the sale items by the mineral specialists as well.
In terms of fossils, a good bulk of them are the typical fare of polished Moroccan orthocerids, polished Madagascaran ammonites, eminently displayable Green River fish from Wyoming, and standard trilobites (common Moroccan phacopids and proetids, mostly, and the usual flush of Elrathia kingii from Utah). Some neat stuff like shrimp from Solnhofen, petrified wood, and the like as well.
The real highlight was in speaking with two vendors, both fairly aged, who are still collecting, and with one collecting locally. There are certain names of collectors, sites, and species we know as we talk shop. It is a small world! One vendor actually knew Charles Southworth personally, so that was a local bit of history.
I didn't buy much, as there wasn't much of interest I wanted to buy (or prices were marked up far higher than what I could acquire them for elsewhere). But, I did buy two things.
A sealed, new copy of what is a kind of trilo-bible for NY collecting (with some significant overlap with similar species in Ontario). I already had the digitized copy of this in my rather robust trilobite book and article library, but sometimes nothing quite beats having a physical book. The photo plates are very nice, and I suppose it may be better to drool on paper rather than on a screen.
And the other purchase: cephalon of an Eldredgeops iowensis southworthi. I don't usually purchase fragments and partials, but it just so happened after all the conversation about Arkona and Charlie Southworth that I figured I'd pick up the trilobite named in his honour. These ones are quite rare to find in the Hungry Hollow Member (a collecting comrade managed to find a full roller of one last October, the lucky duck!). The sheer size of this phacopid is impressive, even in fragmentary form. It differs from the standard Eldredgeops rana mainly in terms of the highly tuberculate sculpture. I do have a small pygidium of one collected some years ago, but this seemed too special to pass up. The vendor I bought this from extended an invite to visit his shop up the highway, and maybe an opportunity to collect with him.
And that's about it this time. With ongoing labour strife with Canada Post, I have a few items coming that will likely be delayed for some while. So far, I am still waiting on some Milliput for restoration work, and two Russian trilobites to prepare (one a new species of Illaenid for me, and the other an asaphid I already have two examples of, and will probably prep and flip).
Until next time...
Unless by dint of some miracle the snows melt away, I think I'll have to call the season. This year has had its highlights and its challenges, and so I would class it as mixed in terms of collecting success compared to 2017. There were some notable challenges this year:
* Late spring and early winter definitely truncated the season.
* An overly hot July and rainy August + scheduling conflicts meant less trips
* My backyard honey hole is pretty much tapped out
* A premium Ordovician collecting site was shuttered to collectors this year
Trilobite collecting diversity was a bit low. Whereas last year I had managed to collect 14 new species, this year's total was only 4. The surge in species acquisitions was mostly supplied through purchases and trades.
Of the trips made this year, a roundup:
* 10 trips to the backyard honey hole with one exceptional find
* A combined 6 days at Penn Dixie (late April, early October)
* My first trip to Deep Springs Road (late April)
* 2 trips to Bowmanville (May and October)
* A combined 15 or so days in the Arkona area
Due to a lack of more local viable sites this year, it meant many of us had to fall back on focusing our efforts on the Widder beds near Arkona, and we managed to excavate extensively this year. The finds were quite good (numerous full Greenops widderensis, placoderm plates, pyritized cephalopods), but somewhat repetitive.
Serious collectors up here in Canada are a little like squirrels. We try to collect as much material as possible for preparation over the winter. Pictured below is 4 of about 5 or so beer flats of material for preparation.
There is more than what is pictured here, but it isn't preparation riches.
Two new areas of focus certainly mark the year. The first has been in the gradual improvement to both my preparation tools/area and skills.
2018 saw the inclusion of that handy trolley, the manifold block for the air tools, a blast chamber my fossil comrade Malcolm made for me, a shop vac, and a new sturdy stool (previously, it was a too-low kitchen chair where the seat was propped up by boxes of rocks with a cushion atop it -- hardly comfortable or convenient). Other stuff include the usual tools of the trade (not all pictured): scrapers, blast media, glues, blades, brushes of all sizes, portable cases, etc. I also now have a nice display cabinet for the trilobites in the living room.
The second area of focus has been extensive reading and research. As I make the transition from "weekend warrior" style fossil hobbyist to something more substantive, I have been consuming a large volume of academic literature on trilobites -- everything from studies on Isoteline hypostome function, biostratigraphy, ecdysis patterns, pathologies and predation, provincial faunalism, eye-blindness trends in evolutionary morphology, microsculpture variation, etc. I also managed to read through the entirety of the trilo-bible, "Treatise O" (the revised Kaesler volume of 1997, sadly not yet including the much-needed two other volumes to round out the rest of the taxonomic Orders). Courtesy of a trilobite worker's kind textual gifts and raiding my own university library, I am effectively training myself to be a subject matter expert on all things trilobite.
IN FOcus: Arkona
Before and after: excavation area #1 (January - October). End of season image does not do much justice to the work done as a lot of debris is already burying the work.
I have been tardy in photographing all the more recent finds from Arkona since my last post about it back in July or August, but there were a few more trips made where I made mostly similar finds as in previous trips this year. Excavation work was extensive this season (and, as I'm the human backhoe, my bar for what I consider extensive is fairly high!). Last season's work became entirely buried by several metres of overburden and debris after the usual processes of winter and the fall of the erosion-resistant widow-makers higher up in the Widder.
Effectively, we had to start from scratch. Pictured above was our first major multi-day foray to get a bite into the cliff from which we could clear out debris and extend benches. It took some doing to locate the productive trilobite layer given that the overburden was obscuring the visible facies, meaning we were flying a bit blind. At the point pictured above, we're still a bit high in the formation by about 1-1.5 metres. Not a bad guess, though, and we were able to work it down and across throughout the season, managing the usual issues of cross-bedding and complicated interlocking of the Widder.
The difference a month makes. In May, Malcolm unlocking new areas. In June from the same vantage point, during Roger's annual visit to Canada, the aftermath of much more removal. We finally hit pay dirt as some remarkable finds were being made at this point after about 7 combined days of clearing and slab hauling.
By the end of spring and into early summer, excavation site #1 is well over 2 metres high, 1-1.5 metres deep, and 10+ metres wide.
Many of us contributed time and muscle to dig this out, with most (solo) visits done by me given that I live the closest to the area and have more ready access. About 12 of us hammered away at this, with a dedicated core of about half of us making repeat visits. By summer, our first excavation was pretty much tapped out unless we wanted to repeat the long clearing process to dig in deeper, which would have meant having to work from the top. We then struck a new claim nearby to the east of the same exposure.
Excavation area #2 was a bit thinner on trilobite pulses. You can see the first area to the far left of Greg.
The slope below the excavation is littered with splits from previous visits. I was able to unlock everything to the right of Greg.
The extent of excavation area #2 just won't fit in a single photo. On this final day, I was able to clear out over 15+ metres to the east. Below the excavation, you can see the massive blocks of the encrinal Hungry Hollow Member. The Widder begins just atop of that and extends to the root of the trees above. The Widder is a strange (and sometimes frustrating) formation where certain faunal intervals repeat, including very dense brachiopod limestone, mushy shale, fossil-poor nodular calcareous shales, and stuff that just weathers to chips and nothingness with poor preservation due to underground water runoff.
In all, it was a substantive amount of focused work to get the site productive again, although I fully expect it to be completely buried by next spring, when the process will have to be started from scratch yet again.
A mostly pyritized and enrolled Greenops widderensis found on my very last trip to Arkona. I have a few rollers to prepare this winter, and such configuration does not lend itself to just basic preparation skills.
FINDS OF THE YEAR
As stated, collecting opportunities were not as plentiful this year due to site closures, weather, and scheduling conflicts. And, of course, the occasional injuries I would sustain from various physical activities. This year, rather than post my best according to taxonomy, some highlights of what made the year special. I am only including here the stuff that was collected, not purchased or acquired as gifts and trades.
Perhaps among my most scientifically significant finds would be this fragmentary cephalic fringe from Odontocephalus sp. found in the imported low-mid Devonian fill (Amherstberg - Bois Blanc - Dundee formations) of my backyard spot. Only a handful of fragments have been reported in the literature in terms of Ontario of a species that is more common in New York deposits. The last significant find of said fragments may be Stauffer's in 1915.
Not just one, but two examples of a new species for me from Bowmanville: Levicerarurus mammilloides. Specimen on the left was prepared by Kevin B., and I have the on the right in my preparation queue (the right eye is in the impression). This is an uncommon cheirurid initially identified by Bill Hessin in 1988, and is restricted to Bowmanville (Hiller Member of the Cobourg Formation). The first one was find in the May trip, and the second in the October trip.
Just a few samples of some placoderm pieces, some of which may be new to science (I still need to deposit them to the ROM along with previous years' finds). The middle one is certainly not new, but a typical placoderm armour plate from Protitanichthys.
This was more a bucket-list item for me. It took three trips to Bowmanville, but I finally found a full Isotelus mafritzae. This one is morph type 'A' due to the presence of the genal spine. I'm still in the process of preparing it, and will be restoring some missing shell. It is only slightly above average size for the species at almost perfectly 100 mm (sag.). I've not seen any specimens that also present such distinct muscle attachment scars on the axis.
Initially just a Greenops widderensis threesome, my friend Kevin's prep skills on my early summer Arkona find produced the surprise of a fourth one. All are enrolled in this gregarious assemblage. As these are body fossils rather than moults, it is likely they enrolled in response to a sudden catastrophic mudslide that effectively buried and smothered them.
Of the four new trilobite species found this year, this would be a short list:
* Odontocephalus sp. (?selenurus) - My thanks to both Scott M. and Dave Rudkin for confirming the ID.
* Leviceraurus mammilloides
* Thaleops sp.
* Flexicalymene croneisi
I was fortunate this year to make new field friends courtesy of their visits to my collecting localities, or to theirs. I was able to meet several new people from The Fossil Forum in person, and many others who are not on the Forum. I made new friends, and cultivated existing ones. In a niche passion such as ours, camaraderie is quickly established (and it helps that we can talk shop without our interlocutors becoming glaze-eyed!).
In the year since I took on a more serious approach to fossil preparation with specialized equipment, I've seen marked improvement in my skills, and I've had an embarrassment of riches in terms of getting guidance from veteran preparators. Some highlights of this year from my "lab":
Although the season has now dictated that I must down collecting tools, it means picking up the preparation tools while dreaming of what new and exciting opportunities for collecting may be in the offing for 2019.
I am reminded of one of Charles Southworth's statements about February, when we stop reminiscing about the collecting season that we've just had and start thinking about the season to come.
Looking ahead to 2019, there are already some new potential opportunities in central New York, in Ontario, and possibly even some digging when I visit Germany next summer. I am also hopeful that some of the sites that have been removed from our list this year will be available next year.
This blog will also not be taking a hiatus just because snow blankets the sites; I will be updating periodically as I acquire new specimens via purchase, and tackle my preparation piles. Stay tuned, and thanks for reading.
A very brief reprieve from the biting cold has meant a small thaw. I did do some poking around at my nearby honey hole, but didn't come away with anything worth showing. So, instead, I've been fiddling with my own fossils at home and exploring the productive postal formation. Let's have a look at prep fun first...
Readers of this blog may recall this slab that has undergone a bit of transformation since I found it back in October. Initially, there were two in the slab, and then I found a third one. Well, I probed some more and this rock keeps on giving.
So what's new? This close-up image tells the story. This is not an impression, but a ventral (underneath) side Greenops. Keep in mind that these guys are very delicate and have a tendency to flake easily even if you breathe too hard on them! This was a nerve-wracking experience as I've never prepped from the ventral side before. I suspect it is complete, but it is uncomfortably too close to a full specimen on top that is not laying directly on top, but that there is a few millimetres of matrix separating the two. If I go too close on the ventral bug, it may shatter the top one. Of course, I can shave it a bit closer, which is what I plan to do when I get the nerve!
Speaking of prep that can make one nervous, this is my new acquisition from the postal formation, courtesy of a trilobitologist in the UK. This is from Mt. Isshamour. Morocco, a Ceratarges sp. nov. from the middle Devonian. It is my second lichid trilobite. Although the pygidium is disarticulated from the main body, it does have those very nice "horns" that at the moment look like mouse ears until I can prep the matrix off (carefully!). The genal and pygidial spines are quite impressive, and it is likely these were developed as a form of protection against predation.
I am waiting on no fewer than four (and possibly more) packages from the postal formation in the next while, which will have to sustain my trilobite fever until winter ends and the collecting season kicks off in earnest.
On Sunday, I had an opportunity to dig in the south pit for about 6 hours. The going wasn't easy: it was cold, for one. And it was very mucky. My goal was to locate full specimens of the two trilobites Crassiproetus canadensis and Basidechenella arkonensis. I have only found fragments in the past, and they occur in the Hungry Hollow Member of the Widder Formation along with Eldredgeops rana and a zillion corals in the coral biostrome. In some cases, there is more coral than matrix! Finding a full one in that layer is not easy as they usually occur as disarticulated fragments.
Arkona's south pit in the morning. There were patches of ice about.
It's early in the trip because I can actually see my boots. By the end of the day, they will be covered in gloopy mud. By my boot is a medium sized coral "pie." I don't really pick up corals anymore.
This is the bench where I've set up for the day. The goal will be to dig into it rather than widen it. It looks quite nice and clean here, but after about an hour the underground water was seeping out and turning the whole bench into orange-grey-brown sucking mud. There were a few mudslides and a rock slide.
It's hard to tell because of all the mud obscuring this rock, but there is a trilobite fragment in here (the darker brown bit in the upper centre). Whenever I encountered a fragment, I put it in the bucket for closer investigation at home. I also brought a spray bottle so that I can see what was under the mud.
So this is what I was dealing with. The rock at the top eventually gave way. The matrix itself is either concrete hard coral cement, or comes out mushy and flaky, but not a lot in between. It is, however, easy to work with on the prep bench. By this time, I'm covered in mud. My gloves are just floppy mud mitts, and my tools are caked. I had to go to the river and wash them off halfway through the day.
Another early win, of a sorts. This is a piece of Eldredgeops rana cephalon.
Thorax and pygidium of a Basidechenella peeking out of the matrix. Into the bucket it goes in the hopes I can discern if it will be a complete specimen.
The cephalon of another Basidechenella. As before, into the bucket for closer inspection at home.
Sometimes one has to chop through a lot of coral. This one just kept going and going. It was about well over two feet in circumference. Here I am chopping out chunks of it to free up the layer.
A chunk of that tabulate coral. Overall, it was a frustrating, cold, muddy day where I didn't have too much to show for it - this being likely my last trip of the year, and thus not ending on a high note. I collected a lot of the usual Arkona stuff like crinoid ossicles, etc., but even scanning the Arkona mud-shale was not being generous as it was all swollen with moisture.
I always collect these when I find them. This is the gastropod Platyceras conicum, which can be easily distinguished from the more snail-like Platyceras arkonense by virtue of its cone-like shape. This one is of a fairly good size and condition.
The sad news is that none of the trilobites turned out to be complete. The ones on the top and the left are Basidechenella, while the one on the right is Crassiproetus.
Using some tools to expose the trilobite a bit more, a closeup of the most complete Basidechenella I found that day.
A closeup on the other side of one of these rocks reveals the pygidium of a Crassiproetus.
So no big wow specimens pulled out this trip, but as my friend Tim says, "a bad day fossil hunting is better than a good day at work."
Until next time.
So began my three day, three quarry adventure. On the first leg of the trip was a visit to my usual haunt, Arkona, but this time it would involve some great visiting friends and fossil comrades (Malcolm, Dave from Philadelphia, and Joe K.). Dave was more keen on plumping up his brachiopod supply, and was eager to get collecting in the south pit. Dave is no slouch on the trilobite front, though... He has gorgeous specimens that I would certainly like to have in my collection.
Malcolm made the long drive to my place and arrived around 7:30 am, and off we went to Arkona to meet up with Dave. But before we left, Malcolm showed me a Moroccan trilobite he had prepared for Dave:
Definitely big props to Malcolm's prep skills. This one has spines coming out in 3D, including a crazy trident protruding from the glabella. Just wow.
This picture was taken halfway through the day. While Dave was off in the south pit, Malcolm and I didn't really budge from our bench in the Widder. Malcolm was heading west, and I was heading east. We moved a heck of a lot of shale. I do not look forward to what will have to happen next once we run out of the left and right areas as that will mean cutting into the cliff, and that will mean chopping out a lot of overburden. I was already having to approach the Greenops-rich layer from the top, cutting out 4-6 feet of shale that only contains bits and brachs.
But the search was a success in many ways. I came away with three Greenops, and Malcolm with two. That's pretty stellar results when finding one full specimen is a trip-maker.
This one is a bit of a bummer given that some parts have flaked off. Still, not a bad piece that I can gift or trade.
I have a habit of picking up nautiloids from the Widder given how nicely they can pyritize. I did find a Tornoceras uniangulare, as can be found in this layer, but it is so pitted and in such bad shape that I'm not going to bother posting a picture of it here.
But the real trip-maker for me was a plate with two Greenops. It also had impressions of other full ones. This must have been quite the death assemblage, and it is a little disappointing that only two survived. But here is how I found it:
Nervous as I was in attempting to prep what would be a $1,000 plate, I just need to make the attempt.
After about an hour using the Dremel to carefully remove some bulk matrix, and a sewing needle to work carefully around the specimen to reveal more of it.
And this after another hour using more sewing needle and the Paasche air eraser using baking soda at 25-30 PSI. Not perfect as this pair has a few problems, but not a bad first try on a very tricky piece! I might do some fine touches on it later.
In all, a good first leg of the trip, and great to meet up again with Malcolm, and meet both Dave and Joe for the first time after only knowing them via the Fossil Forum.
It was just a week ago that we spent all day carving out big slabs of Widder shale from the productive Tornoceras layer above the brachiopod layer. With the weather holding on to summer by its eye teeth, it was an impromptu invitation from a fellow TFF member, Kevin, who is part of a fossil club that saw us loading up our tools and spending our Saturday in the sun.
We began in the south pit. I spent the morning digging into the high energy coral biostrome of the Hungry Hollow Member, picking through the softer, shale layers. Apart from large rugose corals, there are brachiopods, pelecypods, bryozoan colonies, and trilobites. Because the deposition conditions were turbid, high energy environments, most trilobites only appear as fragments.
Pictured here is one of many of the large trilobite fragments that can be found in this layer. The most common species in this layer is Eldredgeops rana. This one is fairly large, even for this site as evidenced by this plump and inflated glabella. Prepping it a bit more, this one is nearly 2 inches wide.
When I first found this one in the biostrome, all that was showing was the glabella. After some prep with a Dremel and then sewing needle, I uncovered more of the cephalon, but also discovered another cephalon to the bottom left. Sadly, neither are complete, but I was happy to bring out some detail.
The second most abundant species in this layer is Crassiproetus candadensis. Pictured above is how one usually finds them: mostly pygidiums. The crushed one on the right has a slim chance of continuing into the rock, but I am skeptical.
By the afternoon, we made our way to the north side, and I took others to my favourite cliff exposure. This spirifer is quite nice as they can be very delicate, so it is not common to acquire a matrix-free one with its wings intact. This one is over 2 inches wide.
I spent almost four hours in the same spot extending a bench and moving about 30-40 cubic feet of shale. I mostly had to remove a lot of overburden and layers of less productive shale to get to my coveted low energy layer that rests atop the hard brachiopod layer, but also has a chance of finding very nicely preserved ammonoids and nautiloids. The productive layer is about 3-6 inches thick. Again, I failed to find a fully complete and pristine Greenops widderenesis, although the fact that they appear mostly complete as opposed to lots of shredded bits increases the probability of encountering one. I collected this for practice prep as I am expecting a Paasche air eraser in the mail in the next week or so.
Of the 4 or 5 I collected on this day, this one was in the middle of a large slab of shale. It took a lot of careful finesse to extract it without having the shale split through it, or the vibration of the extraction process knock off any of its delicate and flaky shell. This one will clean up fairly nicely.
I don't usually bother with fragments unless they have something special about them. In this case, the cephalon is much larger than one typically finds for a Greenops. This one is over an inch wide. Typically, the species is a little over an inch long. On the right is an impression with some of the shell sticking to it.
Last week I found a large and inflated Tornoceras uniangulare. So why not find another one? This one is slightly smaller and thinner than the one I previously found, but the detail on this one is fantastic. I think it is a gorgeous specimen.
Not pictured would be my usual assortment of odds and sods I always found at Arkona. Although once again I was skunked on finding a pristine Greenops, I still made out very well, and got to collect with two members of the Fossil Forum, too.
Lastly, this piece was not found in Arkona, but I rediscovered it while going through a trip bucket. I picked this up from the Verulam Fm in Brechin. Is it a big crinoid head? Nope. It is an ichnofossil; i.e., a trace left by an organism or organisms. In this case, it is Phycodes ottawense. This mop-headed piece is caused by worms burrowing repeatedly into the sediment from the same spot. Worm burrows bore me to bits, but this one was worth picking up due to its neat appearance.
But stay tuned: there will be at least three major events coming up: 1. Cleaning up a lot of fossils with the new air eraser once that comes and I get a good air compressor; 2. A multi-day trip return to Penn Dixie in October; 3. A possible trip back to the Ordovician on the hunt for Isotelus in Bowmanville in late October. Even without those upcoming events, this has already been the best collecting year ever.
Deb and me spent the day at our usual Arkona spot, focusing exclusively on the calcareous layers of the Widder Formation in search of more complete Greenops widderensis. We certainly moved a lot of shale with results that may have fallen short of pristine specimens, but far better luck than we'd been having this year. Having zeroed in on a very productive layer, we were finding more relatively complete specimens rather than just bits.
A mixed bunch of semi-partials on the left, and more complete specimens on the right. Sadly, even the complete ones are fairly damaged or distorted - that's just the way the Widder breaks.
What some of these look like after a bit of prep. The one on the left is likely a complete roller, but far too delicate for the tools I have on hand to prep out better. The one in the centre is complete save for the disappointing damage to the upper right cephalon. The one on the right is likely complete, but crushed and would require far more precise tools under a scope to prep.
A heavily pyritized Michelinoceras was among the circumstantial finds. The layers with the higher percentage of full trilobites rests above the hard brachiopod layer, but will also have its fair share of nautiloids and ammonoids. There is also a thin yet productive layer beneath the brachiopod layer that has several ammonoids, but fewer trilobites overall.
Generally, at this level of the Widder Fm, if it is long, thin, and not straight, it will be a pyritized worm burrow. In this instance, we have the appearance of fairly uncommon crinoid stalk which looks to possibly be terminating in a calyx (only some prep will determine one way or another). This would be the first evidence of crinoid I've seen this high up in the formation.
Ammonoids (Tornoceras uniangulare). The two little ones need a bit of a cleanup, while the middle is a whopper at 35 mm. The big one was wedged between two bedding planes in a large slab I was splitting. Although on the hunt for Greenops, this was a trip maker for me. It is fully inflated and intact - not terribly common for the larger ones in that shale as they tend to come out flattened and crushed. The smallest ones at the site (Tornoceras arkonense) come out of the Arkona Formation, and readers of this blog have seen pictures of several ones I've pulled out from there.
The detail on it is also quite good, and might look even better with proper preparation. Those suture lines are fantastic.
But perhaps the real trip-making prize goes to Deb for this find. This is a substantial piece of the arthrodire placoderm, Protitanichthys sp. (I think). It lacks the plate segments of a Bothriolepis canadensis. Most people just find tiny pieces of fish plate, so this one is a really great find. The exact species is not entirely certain to me yet, but the Devonian fish of the Widder are not well described.
So, although we didn't quite find any pristine trilobites this time, the stuff we found by chance in the same layers was more than worth the effort.
Before signing off, for those who would like to see just the trilobites in the expanding collection, I've created a separate gallery page here. It can also be accessed using the green button at the top right of this blog.