2020 Ontario Trilobite Hunting

[Peat Burns]

26 minutes ago, Kane said:

You do know I am collecting a few of these for you, right?  

Oh, that would be great.  I wish I had some cool, rare trilobite that you wanted for your collection to send you in return.  I'll try to send something, though.  If nothing else you can sell or trade it for trilobites 

[Kane]

27 minutes ago, Peat Burns said:

Oh, that would be great.  I wish I had some cool, rare trilobite that you wanted for your collection to send you in return.  I'll try to send something, though.  If nothing else you can sell or trade it for trilobites 

I'm sure we can work out something. You would come into possession of some trilo-goodies in time. We have several more years to collect and play out there.  If I have some goodies now to send, what is to say you wouldn't have some tomorrow or five years from now? It all works out.  

 

Just let me know what the museum needs.  

[FossilNerd]

6 hours ago, Kane said:

I'll save the stroma for you if you want it.  If there are any other (non-trilobite) things you want from my spots, just let me know and I might be able to ship them out to you when I can.

That is very kind of you Kane! I’d hate for you to go through any trouble for me, but I wouldn’t turn it (or a couple of rostroconchs) down.  
 

I haven’t found a good source of bugs here yet, but know they are around. I have a lead on a Silurian spot that supposedly has trilobites in the exposure. It’s top on my list to check as soon as I can get out again. If it proves fruitful, I could send some your way.
 

Also... When we do meet up at Penn Dixie one day, I’ll do all the backbreaking grunt work, or at least give the Human Backhoe a sizable lunch break.  

[Tidgy's Dad]

8 hours ago, Kane said:

And you, too, @Tidgy's Dad -- I owe you a massive, expensive, multi-location package. Let me continue building your box. 

Thanks a kazillion. 

And good luck with further hunting at the Yoko Onondaga Formation.

[Kane]

Another six hours in the "Yoko Onondaga"  

First up are some obligatory non-trilobite fossils. Gastropods certainly dominated some layers, although brachs remain the most abundant by a long chalk (I did find the large spirifer with the smaller brach hitchhiker kind of cute). Oh, and whenever a rostroconch popped out clean, it went in the bucket.

[Kane]

Just fished out a field photo of some brachs. Oh, and this rostroconch. Look at its size against the measurement grid. By far the biggest example of these I've thus far found.

[Kane]

The monster-sized dalmanitid, Coronura, was only leaving tantalizing, sloughed off bits today.

[Kane]

A real hearbreaker. One can barely make it out, but there is a Coronura pygidium there. It is just so weathered and eroded that all I can make out are a few faint segment lines. 

 

Oh, and this other bit. Not sure if it belongs to this species, so I may have to play the "match the bit with the literature images."

[Kane]

A few more Anchiopsis anchiops bottoms. The last one is calcite crystallized. More on the chappy on the left of the first one next.

[Kane]

Finding an intact cephalon in this material is surprisingly rare. I do know it is a member of the synphoriinae, but not yet sure which of them matches best. If there were a bit more of it, the diagnostic details would make this easier to ID (Anchiopsis would have an occiptal spike, Odontocephalus would have those telltale front margin denticles). 

 

But, when in doubt, I always collect the negative. 

[Kane]

I can make this the fourth of the synphoriinae, and overall sixth distinct species, found in these rocks. Lacking a terminal spine, and with a sharp axial ridge (more apparent in the negative), it is a fine match for Trypaulites sp. 

[Kane]

This last one is very tiny (under a centimetre). I suspect it is just a flattened Trypaulites on account of the number of pygidial ribs. It may be one of the other species, though. There are two: T. calypso and T. erinus. Of course, according to Ludvigsen, neither are reported in Ontario (but were included in his book on Ontario trilobites because of their presence next door in NY equivalent strata). 

[FossilDAWG]

Impressive diversity of trilobites! 

Don

[Kane]

Thanks, Don.  

The diversity is certainly helping with bracketing the zone better. Using the phylogenetic table from Lesperance and Bourque, I am able to provide a conservative estimate on stratigraphic range (light blue box indicates the largest possible range, dark blue the restricted range). This is based on what has been found at the site so far. The description of the Moorehouse Member (comparable to the Needmore in PA) seems the best fit. Sort of. It would be much more precise to map these according to brachiopod association communities, but there are very distinct faunal differences between the Onondaga of NY and Ontario that makes comparisons trickier. Even within the members, there are lithological "repeats" (in the Moorehouse, there are elements of Edgecliff, and a shaly layer called the "false Nedrow"). 

[fifbrindacier]

On 05/04/2020 at 1:23 PM, Kane said:

When the rock is dirty, sometimes the only signal of a trilobite is its negative, such as was the case here. Sadly, the positive was in very poor shape.

 

On 07/04/2020 at 2:36 PM, Kane said:

Spent the afternoon in Formosa yesterday. No showstoppers, but some neat stuff regardless. The little mountain has been changed forever now that I've come with serious tools. 

 

Starting this off with non-trilobite stuff. A good assortment of steinkerns and fossils. Platycerids, nautiloids, bivalves, etc. In the group shot, one of those bivalve steinkerns in the middle has both valves. The large gastropod with the low turret on the right was a neat find, and a healthy size (also shown in hand). That big brach in hand has original shell and both valves. The tiny pair is a high-spired gastro with a tiny rostroconch friend. Deb found the wee rostro. I didn't keep some of the larger nautiloids as I already have a bunch. 

 

3 hours ago, Kane said:

Another six hours in the "Yoko Onondaga"  

First up are some obligatory non-trilobite fossils. Gastropods certainly dominated some layers, although brachs remain the most abundant by a long chalk (I did find the large spirifer with the smaller brach hitchhiker kind of cute). Oh, and whenever a rostroconch popped out clean, it went in the bucket.

 

3 hours ago, Kane said:

Just fished out a field photo of some brachs. Oh, and this rostroconch. Look at its size against the measurement grid. By far the biggest example of these I've thus far found.

I must pay you a visit ! Those rostroconchias are terrible !

[Monica]

So many gastropods and rostroconchs 

 

Great detective work re: narrowing down the stratigraphic range of the rocks, Kane!

[Peat Burns]

On 4/11/2020 at 1:50 AM, Kane said:

 

 

Just let me know what the museum needs.  

If you ever come across any Devonian Hexactinellid sponges, I'd buy or trade for those!

[Kane]

Aye, Sophie...the material at this site is certainly not depauperate!

 

Monica: More work will need to be done on my part to truly fine tune the stratigraphic range, of course. So it is not quite yet as precise as I would like. I just need to be less lazy about identifying the brachiopod communities as a way of determining that. Individual species can be far-ranging, and so it is usually associations (such as, for example, the Atrypa-Coelospira-Nucleospira community, or the Leptaena-Megakozlowskiella community, etc.) that are more diagnostic in determining (bio)stratigraphy.

 

Peat Burns: That would be quite the find! I have yet to ever encounter one... but if I do, you have first dibs.

---

In an effort to be systematic about this year's adventures, I have plotted a series of routes and locations, courtesy of a great deal of poring over the old literature, maps, and satellite views, mixed with good ol' fashioned field visits. A good number of potential spots looked promising via satellite (or 30 years ago!), but in-person visits would tell a different and disappointing tale. 

 

The spots are vaguely indicated on this geologic bedrock map (as some of these are truly honey holes!). The red stars are "proven" and the blue stars are to be investigated. I did not grant a red star to the Arkona area as this would be my first year having not yet visited by this time,  but I've been there enough that I know it is "proven." There are also a number of other locations that I have yet to pin location stars on yet, but I have a list of about ten or more. Some sites would appear outside this map as well. 

 

The colour codes may be tricky to make out due to the small print of the legend, but roughly the green areas correspond to Devonian-aged bedrock, yellow for Silurian, blue for Ordovician. So far, there is a very heavy representation of Devonian sites, but I will be dipping into older material as time goes on, which would invariably increase the chances for more trilobite abundance, diversity, and specimen quality, generally speaking. Devonian areas outside of Arkona are not known for finding full, pristine specimens. Much of the literature that identifies these bugs are based on fragments alone, or by better specimens in corresponding NY age-equivalent strata. 

 

Apart from unique circumstances of preservation / diagenetics, eustatic cycles, coincidental placement as carbonate ramp or sabkha plain during a good chunk of Devonian time here -- most of which does not necessarily favour trilobite specimen quality -- a huge swathe of southwestern Ontario has a paucity of natural outcrops due to the great post-glacial backwash that dumped a good 30-400 feet deep of till over everything. Most other locations (outside Arkona) where the bedrock is closer to the surface (even then, maybe by about 10-30 feet down) are working quarries that do not permit access. This means relying on outcrops that may be minuscule and easily exhausted, or in having to trace the dumped tailings to their original quarry. 

 

[piranha]

5 hours ago, Kane said:

Finding an intact cephalon in this material is surprisingly rare. I do know it is a member of the synphoriinae, but not yet sure which of them matches best. If there were a bit more of it, the diagnostic details would make this easier to ID (Anchiopsis would have an occiptal spike, Odontocephalus would have those telltale front margin denticles). 

 

But, when in doubt, I always collect the negative. 

 

 

The glabellar lobes would be fused on Anchiopsis

[Kane]

Aha! My first hunch may be correct, then. 

Also, I keep using the wrong nomenclature.  Synphoriinae has since been reclassified, if I recall correctly.

The trick with identification of them usually comes down to having well preserved front and back end parts. 

[fifbrindacier]

3 hours ago, Peat Burns said:

If you ever come across any Devonian Hexactinellid sponges, I'd buy or trade for those!

 

3 hours ago, Kane said:

Peat Burns: That would be quite the find! I have yet to ever encounter one... but if I do, you have first dibs.

If you encounter two, can i have the second dibs ? Or even photos of sponges you have, if you have ones. I'm writing a little article on sponges for the paleontologic revue of my club and i've begun a collection of sponges from all over the world and the epochs.

[Shamalama]

[Ludwigia]

Hey Kane. Looks like this is starting to get serious

[Kane]

Time for another long trip report, but one a bit on the shy side for bugs. All part of the process of prospecting, though.

 

A Saturday in the Silurian was in the offing. We put some classic punk on the speaker and off we went to the Niagara region to check out a few spots. First up was a long abandoned quarry, very much overgrown in spots:

[Kane]

We hit a clearing and I went at a check of the strata. It was a good slice of Silurian cake, size-wise, but it was fairly blank inside with mostly very hard mineralization, burrows, muddy lumps, and very rarely a few brachiopods. 

 

It looked nice and promising, but sadly pretty empty. There are some very blank intervals in the Silurian here that can run tens of metres thick. The exposure here from top to waterline was no more than about 3-5 metres, all around a lake that was created when the quarry filled it in.