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. A fossil friend of mine on the Fossil Forum, Jason Rice, recently sent me a package of goodies in trade for some spare material I had on hand from Arkona. The top row has some mouth plates and shells, while the bottom four rows are all fossil shark teeth. These are quite special for me as they represent the first shark teeth in my expanding collection. These are from the Miocene period, 6-20 million years ago. The teeth are definitely worthy of a close up image. This large fossil scallop is Chesapectens nefrens - a fairly popularly sought out one. The trilobite Elrathia kingii from the Wheeler Formation in Utah. Middle Cambrian (~550 million years ago). Another Asaphiscus wheeleri, with impression. It is fairly common that one finds these without their cheeks as they moulted their old carapaces and exited through their cephalons. The most iconic of the Utah trilobites, and the one you see most commonly sold in rock shops, here we have Elrathia kingii with a tiny friend - a "mini-me" version, if you will.
All very exciting stuff! Not only does this boost my trilobite species count for the year, but particularly Cambrian trilobites (see my post on the ones I acquired from Marcus here). As there are no Cambrian exposures anywhere near me, these are a real treat. Day 1 of 3: Craigleith AreaDeb was on vacation time, and so apart from a few beach days and staycation relaxation, we spent three days on the road. Our first stop was Craigleith near Collingwood, and we took the stunningly scenic route through Grey Highlands. The Craigleith area is filled with Whitby Formation shale overlying the Lindsay Formation limestone. You cannot legally collect from the provincial park, but there are a few very tiny spots left outside of the park where one can split a few shales to find a lot of Pseudogygites moults. At the park itself, there is a display area of fossils. Pictured above is a fairly large orthocone nautiloid - they got pretty big in the Ordovician. A complete Pseudogygites latimarginatus. Full ones are exceptionally hard to find as it is more common to encounter enormous hash plates filled with moults. A conularid. A fairly representative hash plate of Pseudogygites latimarginatus trilobites and brachiopods. Pieces from over a dozen in this shot alone. Another representative species of trilobite in the Whitby Formation is Triarthrus. I might be able to free up some of the overlying matrix on this one. It is partially pyritized, although it is tough to make out in this photo. The pleura of an Isotelus sp. in the Lindsay Formation. These small, feathery creatures are also common in this shale. These are graptolites. This is indeed a complete Pseudogygites latimarginatus. A bit crushed and torn, but all the pieces seem to be there. Nice! Day 2 of 3: Oro-Medonte to Gamebridge and beavertonAfter staying in Oro-Medonte / horseshoe valley, we made our way to our B&B in preparation for the big quarry dig on the following day. Although not a fossil collecting day as much as simply a touring of small town Ontario, there were a few rocks around. Deb took lots of pictures of some living creatures like sand pipers, geese, monarch butterflies (so many!), and a cormorant. In Beaverton, we took a stroll along the pier where the sides were shored up by Verulam Formation riprap. The Beaverton riprap: weathered gastropod hash. Crinoid hash plate as part of the landscaping toward the old mill park in Beaverton. We took a walk to Gamebridge's locks system, and then upriver where there were pockets of Verulam limestone. Pictured here as an appetizer to the main event for the next day in the quarry is a brachiopod hash with a piece of Prasopora on the right. By the same river, a crinoid stalk terminating with half a calyx showing, plus the impression of arms flowing from it. A neat piece! Last river piece: a hash of mostly brachiopods and bryozoans Day 3 of 3 (The Main Event)I was so excited to get into the quarry that I was up at 4 am and left the B&B at around 5:15 during nautical twilight to make the five minute walk to the quarry. I deposited the legal waiver forms, suited up with the hardhat and reflective vests, and poked around to look at the rocks the best I could until the sky lightened up a bit more. Those who have read my previous post on Brechin's JD Quarry (here) already know the place is incredibly vast and overwhelming. Top left: a large cephalon and genal spine of an Isotelus (fragments abound here, while full ones are very hard to come by). Top right: more Isotelus bits with a Flexicalymene senaria cranidium in the centre. Bottom: typical busy hash plate of assorted crinoids, trilo-pieces, bryozoans, and brachs. First blood is a prize find: a semi-prone Flexicalymene senaria in the scree at the top level of the quarry. I found it in two pieces and had to stabilize it with crazy glue. Unfortunately, the pin that functioned as the stopper for the nozzle had snapped off, so my glue bottle would be one use only. This piece is still, however, lovely and quite robust. Eventually, I was joined by Malcolm, Kevin B., and Jabali. We split some new blast piles, and also worked on the new area hauling out tons of rock where Malcolm had found some exceptionally rare cystoids. Sadly, it looked like what he had found the weekend before was an isolated death pool, but it felt good to move enormous slabs of Bobcaygeon Formation limestone. Just to give you a sense of how serious we can be, one piece we moved had to weigh over 700 lbs, and I ended up snapping a steel pry bar. Groar! I spent the rest of the day trying to cover ground, going through weathered piles of scree along the upper ledges and wandering the immensely mountainous crush piles. We don't screw around. Jabali snapped Malcolm and me trying to pry this big rock into the pond. We needed to remove from the top down by a good six feet to see if the cystoid layer was going to continue. Bottom of the quarry, new blast pile. Crinoid stalks can run forever here. Close up of crinoid stalks. In situ photograph of a full prone trilobite, Flexicalymene sp. Sadly, as I didn't have any glue left, I wasn't able to stabilize it. The tail piece of this one is now missing. What survived transport. I might be able to very delicately tease out the left side. The pustular glabella is poking out at a vertical angle on this piece. Not sure yet what species this is, but will update when I find out. Update: it is looking like I have myself a Calyptaulax callicephalus. Trilo-pieces. Top right: impression of a pygidium with a margin (to be identified). Centre: Possible Flexicalymene cranidium (to be confirmed - actually no: see picture below). Bottom left: pygidium and some pleurae of an Isotelus. Well, what do you know? I get to add another species to my collection. Thanks to Don C. from the Forum in planting the bug in my ear that this might be an Achatella achates, an uncommon phacopid trilobite. I just picked off some of the matrix here to reveal the telltale diagnostic features of this species. Both plates contain partial Ceraurus. Assortment of trilobite pieces: Flexicalymene, Isotelus. The big Flexicalymene found at the beginning of the dig is joined by a Flexi roller I found in the afternoon. This one in need of identification. I have some ideas, but it's just guesswork at the moment. Some big honkin' pieces of orthocone nautiloid. The one on the lower right I make have to photograph independently as it is the very end of the taper, and with a brachiopod association. The middle one may be Geisonoceras. A hash plate with a gastropod on the left, and some trilobite pieces throughout. A close up of this hash. The cranidium belongs to Calyptaulax callicephalus. Deb found this tiny pygidium. Species needs identification! I love these high-spired gastropods! The majority of these are Fusispira sp., (and others like Hormotoma and possibly the thin one being Subulites) and the cluster on the lower right with the pinched spires is likely Lophospira sp. I can't help but to pick up crinoid pieces. Low-spired gastropods that weather out of the matrix. The one exception is the corkscrew-shaped high-spired gastropod I missed when I took the initial "family photo" of high-spired gastros earlier. A collection of brachiopods. The bottom two levels are a very typical heart-shaped species - various types of Rhynchotrema. Odds and sods: top two rows are sponges and bryozoans. Bottom two rows are trilo-pieces. Bonus Round!Before Malcolm left for the day, he gifted Deb and me some fossils. The trilobites I had found and given to him for prep, and I now get to see them in all their expertly prepared glory - my thanks, Malcolm! This is one of the many pieces Malcolm gave us: segments from a eurypterid (a sea scorpion from the Silurian). The are likely from the quarry in Fort Erie, and so are very hard to come by these days. Readers of the blog will already be familiar with this Greenops widderensis. Some Eldredgeops rana I found at Penn Dixie, after Malcolm's masterly touch. The next three images are closeups to show the exquisite detail. Simply wow.
Stay tuned: on Monday I am receiving a gift of fossils from fellow fossil collector Jason Rice, from Utah! So today I decided to spend part of the morning at that site near my house, the infamous "riprap hill" and associated pit. I've long suspected most of the rocks I split there were trucked in, and have confirmation of that due to the three different kinds of trilobite I've pulled from it (two in the last four months - Anchiopsis anchiops and Mannopgye halli). I had been finding examples of rock from the Hamilton Group, Dundee Formation, Bois Blanc Formation, and the Amherstberg Formation. A good and wide range of Devonian age rocks. As can be seen above, the usual assortment of brachiopods and a gastropod. My expectations were low as I'm running out of rocks to break after four years of scouring the place. Ok, but what about this? I get the line by Morpheus in the Matrix in my head saying "what if I told you everything you knew was a lie?" So at first I was in disbelief: this must be a shell impression, not the impression of a trilobite pleura. But I've seen this before. In the Ordovician. Yes, it is a fragment of a Pseudogygites. The nearest Ordovican outcrop is 300 km away. If I needed further proof, I flipped over this piece of shale and saw a fossil barely bigger than the head of a pin. Putting it under the microscope, it is indeed the cranidium of a Triarthrus. Oookay, then. Confirmed: dumped rocks that span over 100 million years. From a field perspective, this is going to make things much tougher in terms of certainty over finds, but I suppose it means a veritable potential bonanza of finds spanning a much broader range of geologic history.
I was able to spend a solid two hours in the south pit at Arkona this past weekend. The rain went from drizzle to downpour, and as mucky and unpleasant as it might make a sustained outing, the weather this season has been so erratic and rain-soaked that it is nigh impossible to plan collecting trips around (unreliable) forecasts. Still, I made it fairly well in what was mostly a surface collecting operation. The rain brought out the colours of the weathered out fossils very well, making their browns and blacks "pop" for easier spotting. Weathering out of the Arkona clay, I spotted quite a few of these goniatites. On sunny days, at the right angle, the sunlight makes their pyritized surfaces shine and become easily found; in rain, they show up as dark brown against the Arkona shale's light grey. But these are all full specimens. I've arranged these in ascending order of size, and I was quite impressed to find such large ones when a lot of them tend to be hardly larger than the head of a pin. Finding full Eldredgeops rana rollers is not unheard of here, but the place does get picked over so thoroughly that they certainly are tougher to find. This roller (pictured at the bottom) had its pygidium sticking up and my eye was immediately drawn to it. As finding disarticulated pieces are the norm, I was pleasantly surprised when it turned out this one was complete. Pictured above it is a small piece of fish plate. This bumpy piece is a bryozoan. I don't find many of this particular type, and its constellatory arrangement reminded me of when I found that very rare bryozoan at the JD Quarry in June. The amount of coral one has to sift through can be exasperating, but from time to time one encounters a nice piece worthy of putting in the collecting kit. In this case, a multi-cup example where the calyxes are very nicely articulated. A collection of Platyceras spinosum. The one on the far left has still retained some of its stubby spines, while the one in the middle is a juvenile. One little fact about these gastropods is that they were coprophagous (they ate poop!), and so it is common to see them fossilized as being a symbiotic attachment to various creatures, particularly crinoids (although I do have one that affixed itself to a coral). I always manage to pick up little goodies, even if I already have plenty of examples of these already. This assortment is heavily dominated by crinoid ossicles, some with cirra, but if you look closely you will find some tiny nautiloids, brachiopods, and the "button coral" Microcyclus on the upper left hand side. And, finally, below is a short slideshow of some of the above finds under digital microscope at x75 magnification. In all, not a bad haul for two hours collecting in lashing rain! I was able to spend a lovely week in Portugal. In Lisbon, many of the buildings are composed of locally quarried limestone, so you can just look at the walls and see fossils. Sadly, they are mostly oyster fossils with very little detail. I didn't find anything rare or spectacular (but being in Portugal was spectacular enough!). This is a view of Magoita beach. It is rarely visited by tourists, and I am obliged to a Portuguese Fossil Forum member who told me about the place. As one can see, those are massive cliffs, and they date to the Cretaceous period. The deposits are all marine and mostly dominated by oyster shell fossils. I collected at the base of the cliffs where stuff would weather out. We were only there for two hours, so not a lot of time to find all that I wanted. On the way down to Magoita beach, I walked past the fossilized sand dunes - a world heritage site. These have all been hardened by several years of wind and surf. A closeup of the base of the cliffs. From the base of the cliffs again. At the bottom are some weathered out rocks. Some typical oyster shell fossils at the base of the cliff. A nice hash of more oyster shell fossils. A jumble of neat looking turitellid gastropods. Not a fossil, but a pretty cool looking and entirely desiccated little snake. Back in Lisbon, this is from the keep of the Castelos do Sao Jorge. Select pieces from the stuff I brought back home. The two on the right are oyster fossils : Ostrea sp. (Ostrea edulis?). The next one is a deer-heart kind of massive bivalve, possibly Pholadomya sp. Not sure about the clam on the far right, but clams are always a bit trickier to identify because they don't change much over millions of years. This last one is not mine (oh, if it were!). It is Eopelobates sp. on display at the Oceanarium in Lisbon.
Nothing too remarkable about the finds from two trips to Hungry Hollow, the first with Roger, and the second with my Deb. But I may as well post some finds. On the Tuesday trip with Roger, we did scour the north pit, hacked out some slabs from the north river exposure, and ended by doing some surface collecting in the south pit. On the Sunday trip with Deb, we focused on the south pit since the north is filled with deer flies in the dense bush. I looked in vain for the other half. This was worked out of the coral layer of the Hungry Hollow member. Deb splits a coral to get a look at the structure inside. A typical hash plate from the Hungry Hollow member, the layers without as many corals. You can see some trilobite cephalons in there. Brach-encrusted shell pavement from the Arkona Formation. Found with Roger on the north pit part of the trip. Not entirely sure what this is yet (to be updated). Could it be a Basidechenella trilobite glabella? About an inch long. A pelecypod from the coral layer. Lots of stuff going on here. Trilo-bits, a possible fish plate, tons of crinoid bits, a Platyceras conicum (lower left), brachs, etc. Next up are a few of Roger's pictures and finds after he cleaned them up: Roger snaps a picture of me up in the bench. We were finding a few of these pyritized orthocones in the Widder shale. Not in itself a rare thing, but this one is intriguing. These Tornoceras arkonense really clean up well! You can pick them out of the Arkona shale, but they also come out a bit bigger in the Widder shale. One must just be on the lookout for a bit of metallic glint, suggestive of something pyritized - and it could be one of these. This one is a bit of a mystery. It is about 7 mm, but has some strange suture patterns. We're not sure which of us found this in the Arkona Fm, but that is immaterial. It is not a Tornoceras, and neither of us can find this ammonoid described in the usual places (such as the Stumm and Wright checklist or on the UMMP database). Could this be a new and undescribed species?
Deb and I made the four hour drive up to the east side of Lake Simcoe to dig at a quarry in Brechin. This was my first time working an active quarry, and it was exciting (and potentially fairly dangerous if you don't properly observe some common sense and safety precautions). It was about a day and a half of rummaging through the rocks on mostly sunny and hot days. But we didn't come away empty-handed! Deb and me ready on our first day. We arrived shortly after 2 pm. Francie from the Ohio Dry Dredgers and a few of their members were just finishing up. They had just come up from Penn Dixie, and we thank Francie for snapping our picture. I cannot stress enough that this is an active quarry with regular blasting and areas that are not entirely safe, so there is no messing around here. Full safety equipment (steel-toed boots, hard-hats, and reflective vests are absolutely mandatory), and it requires signing a legal waiver before entering the site. On the right is the entrance. On the left is just some of the mountainous crush piles. To the right, I'm hauling our wagon full of gear to the uppermost tier flanked by some gullies. This is a view from the second level overlooking a part of the pit. For a sense of scale, a person standing at that back wall would look little bigger than a dot in this picture. The machines below are quite large. The stratigraphy is mostly Verulam Formation from the Ordovician, with some Bobcaygeon Formation now being dredged out from the base. Again, a bit tough to make out scale, but the drop here is precipitous. That rock near the top could fall at any time, so it is generally a good idea not to be poking around directly at the base of any of the walls. The usual rule is to keep about no closer than a 45 degree angle from the top of the wall. A lot of loose stuff out there just waiting for any tremor to send it all down - and no hard hat is strong enough to save you from a few hundreds tons of limestone crashing down! A typical hash plate rich in crinoid and other bits. I tend to either photograph or take home interesting hash plates, and particularly from places I don't get to collect from very often. It gives a sense of the marine bed. Another hash plate. The Verulam limestone itself is mostly storm-tossed debris as opposed to just the quiet deposition of organisms and sediment over time. In some rocks, you can see the violent wave/ripple of mud having had churned everything. Two more hash plate with some rich biota. If you look very carefully toward the upper right of the second one, you can pick out the tail piece of a tiny trilobite. One of the hash plates I brought home of a storm depost of brachiopods and some trilo-bits. Last hash plate pics, I promise! These are just a few I brought home. The one on the left that is brown fell from the uppermost part of the Verulam and has a good collection of gastropods and a few brachs. A few members of our crew. From left to right: Roger, Malcolm (with the rock saw), and me. Deb took some video footage of Malcolm in action cutting out a nice multi-plate crinoid slab. Malcolm has been a regular at this quarry for several years, and there is very little he hasn't yet found in terms of the large faunal variety present here. Malcolm's infamous no-fooling-around rock saw beside a multi-plate of crinoids (picture by Malcolm) I've been tasked with turning the rock over so that Malcolm can continue his cut to free the crinoids (picture by Malcolm). Some high-spired gastropods (Fusispira sp) and flatter ones. These weather right out of the rocks. New material depends on the quarry to be blasting out new stuff. Deb and I found that splitting the blocks was not getting us very far - most of the stuff to be found is either weathered out, or appears solely on the exposed parts of the rock. The rock itself alternates between thinly bedded mudstone/shale and very dense encrinal layers. Splitting the mudstone usually had traces or were just blank for us. Malcolm found this cystoid (Pleurocystites?), and was kind enough to give it to us. I'll try to confirm the species when I update this post. Crinoid stalk. Certainly not the longest you can find here! Closeup of a branching bryozoan (Stictopicorella?). Malcolm tells me that this is a bit of rare one at the site. I found this in the fallen materials on the second level. It is now been confirmed by veteran fossil collectors Kevin K. and Joe K. as the bryozoan, Constellaria - and this may be only third one ever found at this site. Closeup of a trilobite I pulled from the bottom level. I was really coming for trilobites on this trip, and I was not disappointed. The first one I found in the upper level gullies was a Flexicalymene senaria roller, but this one is a prone and partially/maybe disarticulated one? One of the most common trilobites in this formation is Isotelus, but full specimens are a bit tricky to find. Just about every rock has bits of them. On the left is a collection of tail pieces, with the one on the extreme left a fairly large (4 inches wide) example that Deb found. On the right are some other pieces, mostly of a genal spine, a hypostome (the mouthpiece, which looks a little like a wrench head) and some head pieces (cranidia). This I found on the second level: a ventral view (underneath side) of an Isotelus - or what remains of it. You can see the hypostome. This is a virtually complete Ceraurus missing only its pygidial spikes. It is currently with Malcolm who will be prepping it for me. Trilobite rollers! I had very much wanted to find a complete Isotelus, and I was not disappointed. The "Kermit" looking one on the left is virtually complete and found lodged in the strata on the second level of the quarry. The one of the far right is a Flexicalymene that I had found minutes upon exploring the site, and the middle one is a Ceraurus sp. A closeup of the middle one. I still have a bucket of stuff to go through, and some IDs to put on the finds. In all, it was a fantastic and exciting trip. My thanks to Malcolm for being our gracious and knowledgeable host. The site boasts a heck of a lot of variety for trilobites alone. Below is a table of identified and described species found in the Verulam Formation by B.A. Liberty (1969) Paleozoic Geology of the Lake Simcoe Area, Ontario. Geological Survey of Canada, Memoirs 355. Since then, Ludvigsen (1979) describes a few others, including Amphilichas (a pygidium of which Malcolm found just this weekend, and is considered a rarity - and never found whole). Update: I just performed a bit of light cleaning of the rollers and snapped slightly better pictures of them here:
I spent the entire morning on Saturday at the hill & pit just beyond my backyard. My expectations were fairly low given how much I had picked the place clean over the years, so it was my goal instead to take pictures and record some of the fossil fauna there for posterity. How plans can get upended - sometimes in unforeseen yet lovely ways. This picture is not exciting, nor was it meant to be! I began on the southwest portion of the hill (which is now pretty weedy with burdocks and spiky plants, by the way!). I had not spent a lot of time in that lower quadrant as I always seemed pulled to the upper southwest and southeast areas. Pictured here is a typical brachiopod assemblage - some spirifers, an atrypa-type, a Leptaena, and other assorted kinds. As I said, the purpose was to photo-document the typical stuff of the Bois Blanc Formation. Another very typical assemblage from another distinct layer of the Bois Blanc. This tiny brachiopods can be quite numerous (I forget their name at the moment). So numerous, in fact, that some of the rocks bearing them actually are more shells than matrix, and just crumble. There are several examples of this type of assemblage in the area where the brachiopods are stained a kind of vermillion. A similar assemblage to the first picture - some atrypas, a leptaena, and a large ?Strophodonta. Bored yet? Performed a brief scan of the upper south quadrants and assembled a few of the specimens I had set aside from previous visits. If you zoom in for detail, you'll see, left to right, a rather chunky brach assemblage (name escapes me at the moment!), a lingulid pelecypod, a horn coral, and a typical (for particular layers in the Bois Blanc as a signature feature) cherty rock with a few corals showing cross-section. By this time, I had enough of the hill and was ready to give the adjoining pit another try. Oh, but wait - I was distracted by a rock I had split and left behind some weeks ago. I decided to break it down to pluck two bryozoan specimens. The first pictured above is a typical fenestellate bryozoan. The next is a bit more peculiar... Now what the heck is this? I made inquiries on The Fossil Forum, but at best we might describe it as Sulcoretepora. As described by a single specimen in the Amherstburg Formation by J.A. Fagerstrom: "This specimen is a short bifoliate stem with three rows of apertures on each flattened side and none on the edges. Slightly raised longitudinal ridges separate adjacent rows of apertures. Apparently no mesopores are present between apertures but they may have been destroyed by recrystallization" (17). Fagerstrom, J.A. (1961). The fauna of the Middle Devonian Formosa Reef Limestone of southwestern Ontario. Journal of Paleontology 35(1):1-48. There are some interesting branching, radiating patterns in this one, with two zooecial apertures near the upper left and upper right corner (the dimply stuff). Colony form here is likely remnant of bryozoan encrusting substrate (with thanks for our experts on the forum). But why are we even talking about Amherstburg Formation? Let's keep this flagged for the time being. I was not expecting to find any trilo-butts, but I managed to find about six. So now I am in the pit and can confirm that it contains Bois Blanc formation rocks. I dug this rock out of the wall of the pit, and pictured above is the pygidium of the dalmanitid trilobite Anchiopsis anchiops (which only appears in the Bois Blanc), but missing its full trademark pygidial spike. Some in situ photos from the pit as I work the same rock. The top picture shows some typical assemblages, while the two lower pictures are closeups of the most frequent brachiopods. Trilobite impressions (Anchiopsis anchiops). I took the positives home. After I patrolled the rest of the pit and did not find much more to my liking, it was time to go home and take stock of the finds. Pictured above is a gastropod steinkern (the inner whorl occurs on the reverse side). Beneath that is a nicely inflated clam, and on the right is another spike-deprived Anchiopsis anchiops. This specimen, found on the hill, is the real "meat" of this post. This is not a trilobite that appears in the Bois Blanc, but solely in the Amherstburg formation. The Amherstberg is a younger formation, contiguous with the Bois Blanc if there is no Sylvania formation intervening. Note the nodules on the fringe of the pygidium. Consulting Ludvigsen's 1979 text, Fossils of Ontario. Part 1: The Trilobites, there is a specimen reported that looks nearly identical to this one, but it is simply called Dechenella halli. The name was updated by Ludvigsen in 1986 and recognized as a new genus: Mannopyge halli. Here is a plate from the Ludvigsen 1986 text on the left, compared to my find on the right: Quite exciting, as this makes the 19th species of trilobite in my expanding collection (I've more than doubled it since March of this year alone). Let's learn more about it: "A warburgelline with pear-shaped glabella, deep sigmoid 1s furrow, narrow (tr.) and faint 2s and 3s furrows; no preglabellar field, tropidium, or tropidial ridges. Large eyes located anterior of cephalic midlength; genal spines short. Semicircular pygidium iacks a flat border,-axis with 9 - 10 node-bearing rings, eight faint pleural furrows and incised interpleural furrows, each pygidial rib terminates abaxially as a rounded node isolated by moderately deep paradoublural furrow. [...] No other warburgelline has a semicircular pygidium, and none possesses a conspicuous row of fringing nodes such as that of Mannopyge. The pygidial pleural ribs of M. halli, however, are of the flat-topped warburgelline-type (Owens 1973, Fig. 2), and there is no reason to doubt that Mannopyge is a late member of the subfamily Warburgellinae." (Ludvigsen 1986, 683). Ludvigsen, Rolf (1986). Reef trilobites from the Formosa Limestone (Lower Devonian) of southern Ontario. Canadian Journal of Earth Sciences (24): 676-88. Two remarks: First, this tells me that there are some Amherstberg formation rocks in the mix at this site. Second, trilobites in the Formosa reef limestone are not particularly common, dominated as it is by coral and stromatoporoids. Of the uncommonly found trilobites in that limestone, it is mostly dominated by Crassiproetus, followed by frequency occurrence Mannopyge halli, followed - in descending order of frequency - by Mystrocephla, Acanthopyge, and Harpidella. I'll leave off today with a few more pictures, mostly to underscore that my picture-taking ability has seen a little boost in quality on account of having acquired the third-party app, Camera+, so that I can take proper macros. Using an iPad to take closeup images can be a bit unsatisfactory, but the app I purchased allows me to get in much closer and increase the resolution (which is probably why those of you with slower bandwidth are cursing me right now). As a test, pictured above are two sides of the same piece of crinoidal limestone found at Penn Dixie. And this is a closeup of a coral piece from Arkona. I'm pleased with the detail.
Ok, enough from me until next weekend, when I'll be headed to a quarry east of Lake Simcoe for some serious Ordovician collecting. Until then, thanks for reading! Now that the course I was teaching is done, and the heavy rains are behind us, thoughts turn back to the hunt. The heavy rain system that lashed a lot of Ontario and western Quebec left a great deal of flooding. Fortunately, not as much here, but the rivers and lakes had been dangerously high, making any collecting near them too dangerous. But as it is the long weekend, Deb and I got out to Arkona for a five hour hunt. Overall, not a hunt that bagged the best specimens, but we weren't skunked either. This is the north bank. The photo does not show the proper scale for the bench I worked out. It was already started by someone else, but I was able to lever out two enormous slabs weighing maybe 300-400lbs each. The slabs were partially covered by overburden, so I underestimated their size until I started seeing a crack. But with a lot of grunting and levering with the pry bar, I freed them and rolled them down the hill to be worked on. Anyone who has worked the Widder shale before knows all too well that one has to go almost quite literally through tons of it to find a full Greenops. Instead, hundreds of moulted bits are quite plentiful. There are layers in the Widder almost entirely dominate by spirifer brachiopods, but they are trilobite-poor. Patience and a lot of hammer blows / rock busting can be rewarded. I was able to call first blood on a likely near-complete Greenops widderensis after a few hours working the slabs. Sadly, this one is tucked in the matrix (but can be worked out) and is missing a chunk of its right cephalon. But it seemed a pretty good day for nautiloids. Pictured above are three Michelinoceras sp. This one may be a bit more of a challenge to make out, but if you look closely you can see the spiral shape, with a bit of the texture showing in the upper left (the brassy, pyritized stuff). This would be a Goniatites, and a fairly large one for this strata. And last up: Deb found her complete Greenops (also tucked in matrix, but in better shape than the one I found). On the right is another semi-inflated pyritized Michelinoceras that I'll have to chip out of the rock. Pictured above is a before and after picture of the nautiloid I found, prepped with a Dremel. Came out fairly well, but this is as far as I dare to take it using an engraver. One day, air scribes and compressors will be needed! So that's about the long and short of the five hour Arkona trip. Below are some other odds and sods: Paid a visit to my local rock shop run by two very nice folks. I picked up these two Flexicalymene ouzregui (Ordovician) from Morocco's Anti-Atlas mountains. A busy brach hash plate from the Bois Blanc Fm fill out in my back nine. Nice big brach + impression from the same area. And lastly, another example of Anchiopsis anchiops - pygidium missing its pygidial spike. Lower right I suspect is just a worn and partially buried Eldredgeops rana. Below is a close-up of the Anchiops with some diagrammatic details provided by our Fossil Forum's resident trilobite expert, Scott. "Anchee," as I will call it, is a dalmanitid trilobite, and the way to tell it is by such an incomplete specimen would be the incised axial rings, shown by the arrows in the re-cropped photo below:
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Kane Faucher
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February 2024
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