I've just returned from an almost week-long adventure to Manitoulin Island and surrounding areas. Three of us prospected numerous sites harvested from old literature, word of mouth, and satellite imagery, including a large number of road cuts, ditches, and piles. Most of our more productive and interesting finds came out of the Bobcaygeon Formation, north of Manitoulin, whereas many other sites were the wrong material, tapped out, overgrown, or far too weathered.
In an effort to be circumspect about locations, no site pictures will be presented here -- only typical material and finds. I will cluster these slideshow style by site, with descriptive captions. Not all sites that we prospected will be presented here.
Site #1 - Bobcaygeon FM upper interval
Site 1 was an upper interval of the Bobcaygeon Formation. Much of the Ordovician material around the Manitoulin area occurred in relatively near-shore environments (save for during Whitby/Collingwood time), and are all high energy. This means many of the specimens have been heavily disarticulated.
Site #2 - bobcaygeon fm middle and upper interval
This site contained the middle and upper portions of the Bobcaygeon exposures of the area, and was by far the most productive for trilobite diversity.
SITE #3 gull river fm (?)
This was a cut that has since weathered too much and become overgrown. Most of the horizons were blank.
SITE #4 - ordovician - silurian boundary
Our search for eurypterids in the Ordovician-Silurian contact was not productive beyond finding numerous algal material.
Site #5 - manitoulin fm
The dolostones of this formation contained nothing other than numerous corals and brachiopods.
site #6 - Whitby/collingwood
Locating some Whitby shale, much of it was very dense and largely blank. No traces of trilobites were found.
This site was an aggregate of material from local roadcuts, with some variability of lithology. We were able to map it against a nearby road cut that was quite tall and had representation of every rock type we found in the pile. This was also the spot where the two trip-makers were found.
Overall, this was a long and exciting adventure with two incredible field comrades. There were certainly more misses than hits in our prospecting, but the occasional stellar finds made up for some of the frustration and disappointment. It was no less thrilling for me to find examples of ten new species for my Ontario collection:
Bathyurus (Raymondites) sp.
I'll tie up this blog post with two trilobites that were waiting for me on my arrival home:
I'll be heading up north on a big dig at numerous locations. Today I was able to get out to my Amherstburg/Lucas Fms spot with a focus on Lucas Fm. Why? The Lucas is pretty blank, crystalline, or riddled with nothing but Eridophyllum-esque corals and domic stromatoporoids with a dash of tiny rostroconchs or Amphipora brachs. The sandier layers contain rostroconchs and poorly preserved low-spired gastropod steinkerns. My goal was to perform due diligence as I start filling in the chapter in my Devonian trilobite guide on the Lucas.
Well, the Lucas was not lucky today. Instead, I became distracted with some Amherstburg blocs. Not too much to show, but some lichid pieces.
This is the positive and impression of a lichid fragment with the telltale tubercles. The positive side is almost impossible to make out.
Hypostomes. These are all the same size (about 7 mm wide). The one on the left would likely belong to Acanthopyge contusa on account of how the "divots" are spaced apart, whereas the positive and negative specimen on the right looks more a fit for Echinolichas sp. as the divots are closer together. Again, nothing complete (and likely nothing ever will be in this material), but I think I have more Ontario Devonian lichid material than just about anyone!
Nothing all that exciting or new, but a nice send-off before it's 5-10 days up north to dig into some Ordovician and Silurian material. If I can't come back with fossil riches, I'll at least come back with good memories breaking rock with a great field comrade. Until then...
I spent the last two days in the field, prospecting about nine different spots and coming up fairly empty-handed. I'll chalk this up to practice, and performing due diligence in crossing off possible locations to better identify the productive ones.
The first day was close to home, mostly sifting through glacial erratics.
These would be a positive and negative of a poorly preserved pygidium in Amherstburg Fm material (and the thinly-bedded, bituminous, crumbly, trilo-poor stuff). Judging by size and other morphological clues, I would label this a Trypaulites sp.
The remainder of the day morphed into a challenging three hour hike in the woods, so not much by way of further fossil opportunities for the day.
On the second day, Deb and I met up with our dear field comrade to inspect about seven prospective spots beginning with an outcrop section of the Dundee Fm listed in a relatively recent dissertation, and then to the lower Devonian Bois Blanc Fm, and finally to a number of Silurian locations around the Niagara region. I am not one to post location photos anymore for obvious reasons, but it would be hard to place this location and it really doesn't have much to make going back there worthwhile as it is mostly just reefal madness. This is Dundee Fm, and it had absolutely nothing but coral and a few bryozoa. Not even brachiopods.
That is a single coral with likely a second branching off it. The length extends to the full frame of the first image.
This location is all Bois Blanc Fm, but sadly not the right horizon. In terms of biodiversity, a single brachiopod was found, and two scarce gastropods; everything else was entirely reefal material of corals, crinoids, and bryozoa.
Case in point would be these hashes. There is virtually nothing here but the coral, crinoid, and bryozoa salad here.
And let's not forget giant coral colonies.
The Niagara region is filled with likely hundreds of creeks vermiculating across its landscape. This is one of them. The strata on the right is quite distinct, and not gradational. The yellowish dolostone is likely Lockport Fm.
A giant millipede. We did find a good chunk of Rochester shale, but it was entirely blank, and not even the hard-ground limestone lenses had any fossils. This stuff would be brutal to try and work with, as it is wet and just weathers out as chips -- a bit like some intervals in the upper Widder Fm.
This would mark my second big attempt to find anything of interest in the Silurian of Ontario. I've covered a good stretch of it in the north (Bruce Peninsula area) and now the south (Niagara), and have yet to hit proverbial pay dirt. In this recent trip, we covered about 500 km and did not prosper. To my disappointment, I have yet to collect a single fragment of Silurian trilobite from Ontario despite a great deal of research and effort. Perhaps the Silurian is a cursed geological period for me! We do have to keep in mind that just about over half of the Silurian exposed in a narrow band in Ontario from St Catherines up though Tobermory is Salina and Bass Islands -- both unfossiliferous units when this part of the world was salty sabkha. Of the other half that are fossiliferous units, about half or more of those were very poor preservation conditions, and the other half is generally inaccessible. I may just have to cheekily rename the Silurian formations in Ontario along the lines of "and here we have the Bugger All Formation, which lies conformably over the Utter Crap Formation, and contains the Nada, Bupkis, and Blank Members."
I will leave the Silurian alone for a bit and refocus on the Devonian and possibly the Ordovician as early as next week.
It's been a bit of a fossil famine as of late. The heat has been pretty fiercely oppressive, but it has been more the issue of not having much collecting opportunities on account of sites that are tapped out, temporarily or permanently inaccessible, and the need to prepare for the upcoming school year by pre-recording a monstrous amount of lecture content. But it is also a dry spell I hope to break in the coming days and weeks.
For now, a few minor trilobitic items just to keep the blog warm.
A fairly sad ensemble, but these were pretty much all that was to be found at my Devonian salad location. Upper left is likely a ventral cephalic fragment of an Anchiopsis anchiops, and the lower left is a busted butt of a Burtonops cristata. I may have effectively drained the site of its riches. These samples above were not worth taking home.
A snapshot of a section of my Amherstburg/Lucas Formations fill area near my home. This would be the area I would concentrate on, with understandably low expectations given how hard and often I've hit this place since I bumped into it last August.
The productive rocks are scarce at this point. Above we see the typical proetids of the Amherstburg: Pseudechnella sp. and Crassiproetus crassimarginatus.
This is culled from two of the productive rocks. Nothing I don't already have numerous examples of. Top row is Crassiproetus crassimarginatus, second row is an unknown, a Trypaulites sp., and a Mystrocephala stummi. Third row is a big Crassi, another Mystro, and some disarticulated Crassi thoracic segments. Bottom row is Mystrocephala stummi, Pseudechenella sp. Acanthopyge contusa. At least I found a lichid bit.
This was a purchase from a forum friend. An effectively complete, albeit somewhat roughed up, Odontocephalus aegeria from the Needmore shale of Pennsylvania. Given my excitement over the genus after locating fragmentary specimens here in Ontario, I was hankering for a complete one to function as a kind of lucky charm for when my Moorehouse Member site becomes accessible again, once the water levels drop.
I have two more trilobites coming from the Purchase Formation, so to speak, but right now the operative focus is on getting back out there, and prospecting new sites. Fingers crossed that this blog doesn't go into another prolonged radio silence!