Day two saw Deb and I make the 3.5 hour drive to the quarry in Brechin with its diverse Ordovician fauna in the Verulam Formation. We had quite the crew with us, and about four are missing from this picture (actually, five, as Deb is the photographer).
Deb and I were the late arrivals (11:30 am), while just about everyone else had been there probably since sunrise! I actually didn't meet up with everyone until the day was done; they were done at the base of the quarry hacking things out of the blast piles and the underlying Bobcaygeon Fm, while I was busy on the upper ledges doing some surface collecting. I've never had much luck splitting at this quarry.
In about four hours of collecting, I barely made it even a quarter around that one long ledge. I climbed a slightly higher ledge and saw that someone had been there before me hacking some layers out. We use marking tape (or actual markers and piles of stones) to let other people know that these specimens are claimed. It would be considered bad collectors' etiquette to take someone else's claimed finds. We do this when our extraction equipment is parked on the far side of the quarry with an intention to return later. Pictured here is a very long crinoid stem.
Another "off limits" beauty: a damaged but still impressive Endoceras proteiforme, the biggest nautiloid species in this formation.
A typical hash plate to show a snapshot of the marine floor from 450 million years ago.
Although just the impression of a partial pygidium, any piece of this rare trilobite Amphilichas ottawensis is worth picking up. This is a new species for me.
Probably the biggest Prasopora I've found at this site. They are fairly common, but this one stood out for its size.
The nautiloid fragments here can get quite massive.
Assorted goodies here. At the top is a nautiloid fragment, to the left is a trilobite burrow (rusophycus), and on the lower left is a tiny shell hash.
Top row: mostly Rhynchotrema capax - quite abundant in the formation.
Middle row: some gastros, including Lophospira, Fusispira etc.
Bottom row: two pelecypods (from Bowmanville!), two trilobite fragments, and a bryozoan.
Another assortment. Of note in this piece would be the very nice gastros here, but also the Ceraurus cephalon at the lower left next to a 2/3 complete Isotelus gigas and another nautiloid fragment.
Did someone say Isotelus gigas fragments? Here are a few I picked up. The fork-looking piece in the lower middle is the hypostome (a kind of biting mouthpart that appears on the ventral side below the cephalon).
My prize finds for the day: a finger-long gastropod, a small but 2/3 full Isotelus gigas, and two full Flexicalymene senaria rollers. The one on the left is quite inflated and looks like a fat cartoon duck when looking at it from the side.
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?
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!