I spent four hours Monday at my nearby spot with the Amherstburg and Lucas Fm material, and likely split the last remaining viable rocks in the former that could potentially have bugs. The rest is pretty much stromatoporoidal Lucas Fm trash.
A really sad split. This would have been a fairly good sized Trypaulites sp. pygidium, but it just wasn't worth taking home. And so ends what was once a very productive location. I hoovered it well, draining it of its bugs. There may be some stragglers in some of the harder, more blank material, so it will remain my site of last resort. It lasted for well over 100 visits, and it has been very kind to me in giving up 7 different species of trilobite, 3 of which were new to my collection, and 2 of those being exceptionally rare lichids, and one dalmanitid that has never been reported in Ontario rocks. I never found anything complete, but I came close twice. The Devonian in Ontario is a big tease.
I'm fairly thorough and persistent, and so can say I've emptied two honey holes in my immediate vicinity. But a new one cropped up today. I've been meaning to have a look-see at this very large location for a while. It is certainly filled with layers upon layers of sand alternating with water-worn rock that spans the lower to middle Devonian, interspersed with lots of igneous and metamorphic gumbo. At a depth of about 300-500 feet, it is steady waves of glacial backwash. You'd likely have to dig a mile to hit bedrock in this town.
Devonian formations present include Bois Blanc, Onondaga, Dundee, and even some paper shale filled with Leiorhynchus that you find in the Hungry Hollow Member in Arkona. I started finding pretty sad Eldredgeops rana bits, but that was a sign of more to come. This was only meant to be a quick recon, but this place is massive and takes a while to traverse.
To the highlights, then...
This is the only E. rana I picked up and will show here. Why, because it's a roan red rana, that's why. This appeared in some Dundee material that is just littered with tiny red brachs all the way through, like the rock is infested with fat mites. The same process of mineralization that turned them red seemed to have worked its magic on this pygidium.
This battered bug bit is not even worth focusing the camera on. If, as my field comrade Kevin says, E. rana is the cockroach of the Devonian, Pseudodechenella may be a close contender for that title. Both of these have a very long stratigraphic range. No, I didn't take this one home.
Now this is where I get excited. Dalmanitids. These are not bad at all in terms of preservation, and possibly a bit better than how they come out in the material at my secret Onondaga spot. These both came out of the same rock. In fact, all the following Anchiopsis anchiops were found in it. This was truly a good rock that seemed to be a moulting ground.
The tails come paired with heads. The one on the left is sadly just an impression. The one on the right is likely complete, and I just need to do some cleaning and light scribing to reveal it in full. I've never found a full cephalon of this species before.
More bits and pieces.
No, it is not a fossilized chihuahua head, but an impendent hypostome belonging to Anchiopsis anchiops. This is the better of the two I found. This was a great rock. If I could find a lot more of it, I would be splitting all day.
And what is that pustular bit in the centre? Likely a Coronura bit, so make that species number four at this location.
So that was a nice three hours of exploring. I do plan on going back, of course, and it's nice to add another hot spot to the prospect list. I am hopeful my new backpack comes soon as I'm not sure if my current one will hold up for another adventure. Although my tactical pack is barely a year old, it is torn in a lot of places, and the straps have had to be tied and knotted to other hoops and loops several times. It doesn't help that I carry around about 30 or so pounds of tools in it, and then add another 20 pounds of rock. The thing was bulging at the seams, threatening to burst. Not what you want to have happen in the field, far away from home.
Site knowledge: it's a Devonian buffet. There is no sense in creating a trilobite list associated with the stratigraphy because the rocks are transport erratics from all over.
In other fossil news, I have created a fantastic prospecting field document for Silurian trilobites of Ontario, and am eager to get on the road to trial its effectiveness. Obviously I won't post that here unless my goal was to ensure others would scoop up everything first. But, a few of my field comrades will hopefully benefit.
Tomorrow looks like a rainy, ice-pellety day. A good one to do a bit of prep. On Friday it is back to my secret Bois Blanc spot to do a whole day's work. Stay tuned!
How niche a topic can I make it? Yes, today's post is about hypostomes, and more particularly, the hypostomes of lichid trilobites (of the Amherstburg Formation).
Ever since stumbling upon my Amherstburg fill area back in August, I've certainly been fortunate to crack open many a rock to find the occasional fragments of lichids, from isolated pygidia, cranidia, librigena, and even a connected thorax (just the one time, recently). and hypostomes.
The thing about hypostomes is that they are very easy to miss for a lot of collectors in the field. They don't look trilobitic to anyone who isn't already familiar with the ventral morphology of a trilobite. When I first started several years ago, I probably left dozens of them in the field. There has been much discussion and speculation on the purpose of this hard, plate that appears just underneath the cephalon, and just as much variety in morphology (check out the spooky and fierce-looking Hypodicranotus hypostome in Ludvigsen's paper here!). It is generally agreed that they served a primary purpose as part of their feeding apparatus. On that discussion, I highly recommend Hegna, T.A. (2010) The function of forks: Isotelus-type hypostomes and trilobite feeding. Lethaia, Vol. 43, pp. 411–419.
This snip of four line drawing representative lichid hypstomes is from page 188 of the lichid bible, Thomas, A.T., and Holloway D.J. (1988). Classification and Phylogeny of the Trilobite Order Lichida Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, Vol. 321, No. 1205 (Aug. 26, 1988), pp. 179-262. There are similarities among the genera's conterminant hypostomes, but also distinct differences as seen above.
At present, I have been able to reasonably identify three lichid genera from this material: Acanthopyge contusa, Echinolichas eriopis, and Echinolichas sp. cp. hispidus. These are consistent with equivalent strata in New York (see Whiteley, Kloc, and Brett's Trilobites of New York, or "TONY" among us bug enthusiasts).
Here are three hypostomes I have found since autumn of last year, with the one on the far right being a recent (as of today) find. I would guess that the first hypostome belongs to an echinolichine, whereas the middle one is unmistakably Acanthopgye contusa. The third one is still undetermined to me as of yet. It seems to share the echinolichine shape, and yet also appears to possess the granular ornamentation of the Acanthopyge. It is also by far the largest one I've found, with a width of just under 20 mm. That would possibly make the original owner between about 70-100 mm in length. Not excessively large, but not tiny. Of course, the preservation could be much better on the last two, but I take what the rock will give.
Hopefully in future posts about the lichids I can start organizing some of the other body parts, too.
Been moving tons of rock the last few days -- quite literally, in fact. I call it training for when society collapses and we're thrust into the world of Mad Max. Not quite, but it has been nice to get out and dig more. Here is a sequence of events of removing a single big rock:
Fun times! And what was in all that rock? Nothing much! Them's the breaks sometimes. The thing about this material is that you never know. It could look promising on the outside and along the visible edges, or it may be blank, but what is inside can only be determined by actually breaking into it. This rock was wide and very deep. It was also wedged and jammed in by every other rock, which in turn was wedged and jammed in by other rocks, ad infinitum. Sometimes the rock wiggles like a loose tooth, but just won't give.
So, any finds from my spot for all those many hours? I've bagged a few more lichid fragments (one of which was a real heartbreaker as it was the edge of an exquisitely preserved pygidium with all the pustules, but it started just before the edge of where the rock stopped. Argh! A number of very wee Mystrocephala stummi pygidia, the usual pygidial/genal/thoracic/cranidia assortment of Pseudodechenella sp. and Crassiproetus crassimarginatus that I'm leaving in the field. But here's something pretty:
A rostroconch (Conocardium cuneus). Rare as all git-out everywhere else but here. At this spot, I'm up to my back teeth in these things, spanning in size from a few millimetres up to 10 centimetres. Both the Amherstburg and Lucas Fm rocks at this location are well stocked with them. If nothing else could survive in the environment, or preserve well, these would.
And now for something ugly:
It's a complete Pseudodechenella sp. -- complete if we mean missing a tail and its cheeks. There's a bit more under the matrix, but not that much more. I might be able to expose the other side of the thorax at best. This one was lodged in a massive block buried several feet deep with only the top showing. Oh, and forget about reliable bedding planes. For the added challenge, it will appear on a rounded bump on the edge of the rock. Extraction was a bit nervy on this one, and it still shattered off a bit -- and that's why I carry super glue in the field for this kind of battlefield medicine.
I will likely make a few more trips to this spot even if the gains are minimal. I'm just biding time until Deb is free so we can get out collecting at a few other spots I need to check. We're also getting a new car (well, used, but a newer model with really low mileage), so it should hopefully not cack out when we're en route to somewhere like, say, Bowmanville for a dig that is now much harder to join up with these days. Losing my spot last October was really depressing.
I don't foresee any new updates this week unless I come away with something amazing. Most of the other stuff -- not pictured -- is just the same old stuff. Finding a complete trilobite in this stuff is about as likely as finding an intact strawberry in your daiquiri, such is the nature of the facies. It won't stop me trying to beat the odds of this Devonian casino in trying to find that mystical, complete lichid.
Since my MMA classes are canceled for the next few weeks, I might be able to get caught up on my trilobite drawings... I have a Damesella and a Metapolichas in the queue, but both are pustulose which equals beaucoup time to render.
More notes from the Devonian underground soon...
Well, now that it's the apocalypse, what better thing to do but avoid the drummed-up panic of the masses and go out for some bug hunting? A great thing about fossil collecting is that the chance of contracting the coronavirus from the Devonian is infinitesimally small. As my university has canceled classes in preparation to move everything online, it sees me with some free collecting time. Of course, I'll be revising my materials to be digitally migrated, and undergoing the final big wave of grading, but I may be able to sneak away a bit more often.
Today was another visit to my Amherstburg/Lucas Fm site. A lot of rock was split, almost all of it massive armour stone frustratingly rooted deep under every other rock. For all the rock split, just about none of it was of any interest to me -- just the same old, same old.
In the image above, I've already popped off the cap of this armour stone. Well, actually, it was a lot of digging, and then driving the chisel with the sledge for eons until all my bones rattled. There were a few traces of proetids amidst the usual coral clutter, brach bumpf, and bryozoan bunches. So, nothing really worth keeping. A few neat gastropods were encountered (a platycerid, and a high-spired steinkern in the chert of another rock). But the real find to make this post worthwhile...
Although a bit in rough shape, this is 2.5 cm of lichid. More importantly, is that it is a lichid with both pygidium and thoracic segments. Equally important, perhaps, is this is likely an Echinolichas sp (cf. eriopis). In Ontario. Two-thirds complete. There's a bit more hiding underneath the matrix. I doubt it will have its head, but -- who knows? I almost didn't see it as it blended right into the background matrix. To the best of my knowledge, I don't think a 2/3 complete and intact example of this species has ever been found.
Definitely a trip-maker. Got to find all the amazing lichids during the end of the world!
UPDATE: As a fellow trilobite expert pointed out to me yesterday, if it lacks the medial axial spine, then it may be a much better match with Echinolichas hispidus as opposed to E. eriopis. Here on the left is the illustration in Hall and Clarke (1888) matched with the photos of my specimen (thanks to S.M. for the stitching!), and on the right is a photo of the holotype (NYSM 4553) in Thomas and Holloway (1988).
In E. hispidus, in place of the large spine is little more than a basal bump. Of course, given the poor condition of this specimen it cannot be stated with great certainty that this belongs to one species or the other. After some light scribing to reveal more of the pygidium, I am leaving it be until I can get it in better hands to reveal more.
As it is so faint and blends with the matrix, I have experimented with different lighting as well as creating a negative in the hopes of sussing out more diagnostic details. This will be a study piece for the time being!
To recap, this is certainly rareness factor 3: firstly, a Devonian lichid in Ontario, even as a fragment, is quite rare as only two species are officially reported and confirmed in the Formosa Reef and the Bois Blanc Fm (with some questions of others having been cited by Stauffer in 1915); secondly, it is exceedingly rare to find a specimen here where it is not just an isolated pygidium or cranidium, but a pygidium with its connected thorax (those tend to disarticulate quickly); thirdly, a species not actually reported in Ontario rocks (but in corresponding NY rocks).
Image credits (and further reading):
Hall, J. and Clarke, J.M. (1888). Palaeontology VII. Containing descriptions and figures of the trilobites and other crustacea of the Oriskany, upper Helderberg, Hamilton, Portage, Chemung and Catskill Groups. Geological Survey of New York, Natural History of New York, Palaeontology: Volume 7:1-236
Thomas, A.T. and Holloway, D.J. (1988) Classification and Phylogeny of the Trilobite Order Lichida. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, Vol. 321, No. 1205 (Aug. 26, 1988), pp. 179-262
Not that I want to jinx anything, but it looks like we have a few weeks of mild weather to look forward to, with possibly Sunday my first post-winter return to the field. It will be another engagement with the Amherstburg Fm material, but I have been quietly developing plans for new prospects.
In trilobite news, with the very recent publication of Bignon et al.'s paper, there are now 14 Orders of trilobites:
Agnostida SALTER 1864
Asaphida SALTER 1864
Aulacopleurida ADRAIN 2011
Corynexochida KOBAYASHI 1934
Eodiscida KOBAYASHI 1939
Harpetida WHITTINGTON 1959
Lichida MOORE 1959
Odontopleurida WHITTINGTON 1959
Olenida ADRAIN 2011
Phacopida SALTER 1864
Proetida FORTEY & OWENS 1975
Ptychopariida SWINNERTON 1915
Redlichiida RICHTER 1932
Trinucleida BIGNON et al 2020**
The Trinucleida were once a superfamily in the Asaphida, but have now been elevated to full Order status. And, to be honest, comparing the appearance of Trinucleids and Asaphids, they seemed an odd match insofar as they appear to differ more than they appear similar. All that being said, I'll need to revise my trilobite gallery to reflect this (and about three other Orders I've been too absent-minded to add) -- something for a rainy day. For now, another drawing:
I also experimented with some mid-tone paper, but just a really quick sketch:
So that one is just a draft for now, flagged for redoing it properly.
And this Moroccan phacopid came in the mail. I actually did not have an example of Zlichovaspis rugosa, and the price was too good to pass up. The quick snap of the bug hardly does it justice in terms of its impressive size. This is not a premium prepared bug -- visible scribe marks and a coating to hide a few mistakes is pretty customary for a B-grade bug, but even those can command high prices. In this case, I got it for a very good deal.
I am just more excited at the moment about getting back out into the field. The snows are quickly receding. I've been digging into Stauffer's 1915 text on the section featuring the Amherstburg/Onandaga material, which seems to be the most comprehensive I've seen in terms of a faunal list (albeit a number of those taxonomic designations have been revised significantly!). And, with just four more weeks of classes, serious field time cometh! Hopefully I'll make out okay this Sunday to post some finds. Until then...
On Wednesday, Friday, and Saturday, I managed to get to my nearby site for more challenging rock splitting. On Wednesday, I found a second cephalon example of the lichid Acanthopyge contusa (see the update to my post here). Friday was a bust apart from the usual fauna, taking home only a few common proetid partials and a few unknowns that turned out to be nothing interesting when I got them under the microscope. Today (Saturday) seemed to make up for Friday's failure.
These are the tools that come with me in my backpack. I added the small pry bar today. Some of these rocks are veritable boulders that run deep, and since they are already extremely tough material to break, nothing comes easy. Even when the material doesn't shatter uselessly along a diagonal across the bedding planes, smaller chunks like to split vertically rather than horizontally as the beds can be so thinly packed and dense. Finding the right rock usually comes down to certain external features, but even then those can be blank duds or simply sparsely fossiliferous coral zones. Before committing to any larger rock, I test the edges to see inside first. The tool most often used in my arsenal at this location is the hand sledge.
When I say typical fauna, I mean the litany of fenestellate bryozoans, brachs, and trilobite partials. When I "test" the rock, these are the kinds of layers that usually show the most promise.
I am tentatively going to label this Acanthopyge contusa, although I am not fully certain it might not be another Terataspis as they have similar pygidial morphology. In some aspects, it seems to resemble both, but the preservation is not the greatest on this specimen. Going with the more conservative estimate, that would make Acanthopyge example number three.
Every split requires a careful scan so as not to miss something spectacular. I almost left it thinking it was a compromised brachiopod, but the notch on the bottom made me think it might be a hypostome. And, surely enough, it is a hypostome belonging to Terataspis grandis. Pictured on the right is the illustration by R.P. Whitfield (1897). That makes three examples of this rare lichid, although compared to those found by others and housed in museums, mine are all quite small. This example is barely 1 cm, while the one at the ROM is 7.5 cm. Still, a mini-monster is still a monster!
Sunday update: Spent another five hours out back and I would say these two partial examples of Acanthopyge contusa were the star finds:
Wednesday update: Another three hours as I steadily run out of viable rock. This is one specimen split between both halves of the rock. It is my fourth fragment of a Terataspis, specifically the genal spine. My tally now is two pygidia, a hypostome, and a genal. The likelihood of finding a complete one is along the same odds of winning the lottery, but how many trilobite collectors can lay claim to having even just a single fragment?
I'll be off this weekend to my secret Ordovician location up north, so I hope to post my finds when I return.
I've spent many days over the last two weeks scouring my new local site. I've pored over the literature and attempted to do a systematic analysis of the fauna in each of the rock types, taking extensive field notes. In terms of finds, not counting the numerous Crassiproetus pygidia and Pseudodechenella pygidia and cheeks, there are more days I go home empty-handed rather than dancing on air.
On the third consecutive day at this site, I managed to locate the right type of rock that is generally highly fossiliferous. This type of rock is in a minority at this site, and I've already split through any of the visible examples, leading me to dig under other large rocks in the hopes of finding more of the "good stuff."
The trilobites almost exclusively appear in rocks that contain large fenestrate bryozoans. The environment was shallow marine reef (owing to the massive presence of reef-builders).
Here is Echinolichas sp. fragment number two:
I collected the positive and the impression. It is in pretty rough shape, but any fragment of this lichid will come home with me. So is the matter settled about the strata being Bois Blanc? Hold on. Also in the same rock was this:
The top image is a capture from Rolf Ludvigsen's Fossils of Ontario Part 1: The Trilobites, and it shows a cephalon of the lichid Acanthopyge contusa. The image below is my find. But this is reported in the Amherstburg / Formosa Reef. This was already a bit confusing!
Terataspis is only reported in the Bois Blanc Fm. If this were Bois Blanc material, I have not seen even a trace of Anchiopsis in the large volume of material I've gone through. Acanthopyge is only reported in the Amherstburg, and although volumetrically the abundance of Crassiproetus is indicative of this formation, it is also a poor index given that it prevailed across several strata.
Riddles upon riddles aside, I am happy to welcome my second Terataspis, and a brand new lichid to my collection!
Stay tuned, for there is still a very large source rock for me to break down that weighs in excess of a metric ton. It is where the Terataspis was found. More to come this week, I hope!
Update, Sept 18, 2019
I found a second cephalon example of Acanthopyge contusa:
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!