2020 Ontario Trilobite Hunting

[Kane]

We changed locations, but not the formation. These appear a bit lower in the formation than at the ditch. Isotelus bits were the first to greet us. Pictured here as well as a chunk of nautiloid, what may or may not be a complete Ceraurus or Gabriceraurus in ventral position (I may need to flip it and prep from the other side). But it shows its hypostome. And finally a line up of giant ostracods.

[Kane]

The first photo is the pygidium of a Bathyurus (Raymondites) longispinus, no less neat because it preserved the pygidial axial spine intact. Second photo is just the usual Rhyncotrema, a coral, and a small Maclurites. I need to take a photo of the fist-sized one of those I fetched from a nearby site there. Third photo is of a nearly complete receptaculitid, and the fourth a partially buried Isotelus sp. pygidium that I revealed much more of, but didn't keep on account of it being so poorly preserved.

[Kane]

A large bryozoan followed by a recto verso pair of images of a nautiloid chunk, and finally the ventrally oriented Isotelus fragment showing its doublure.

[Kane]

A pair of bashed up, headless Bumastoides.

[Kane]

1. A very large styginid (about 6 cm across in its fragmentary form, and complete might have been up to 15 cm long). It is possibly Failleana indeterminata, but it will need better confirmation.

2. A headless but uncommon trilobite, Ectenaspis homalonotoides. This asaphid is similar in morphology to Megistapsidella. Quite a treat -- and a bit rare, too!

3. We reasoned that this disarticulated mess is Eamonarachus intermedius, which is very similar to Calyptaulax callicephalus but differing on a few features of the genal spines, tuberculation on the glabella, presence or absence of incised median pygidium segment furrows, and size of palpebral lobes. If it is indeed this species, it is usually restricted to the Manitoulin area and is quite uncommon. 

[Kane]

We started another of our days at a cut reported in the literature that had become overgrown and far too weathered in the 40 or so years since that paper was written. The first two photos include Isotelus bits, and a mess of what may be some kind of crinoidal or edrio material. 

 

The second pair of images include the only site photo I can share publicly. We had made a foray to where the Ordovician-Silurian boundary is in search of eurypterids. Long story (and drive) short, we only found algal bits (last photo). This was a tough spot to search as the only productive layer is at the base of this very hard and blank dolostone, requiring having to pull the more argillaceous and platy layers out from the productive horizon.

[Kane]

We then ventured into the Manitoulin Fm (Silurian) where there was an abundance of dolomitized brachiopods, coral, and little else. I kept the coral in the last picture as a souvenir.

[Kane]

We ended day two exploring a pile of Whitby shale that was cut out of a ditch. It was a very hard and mostly blank shale with some pyritized nautiloids and graptolites as pictured here. We also visited the one small spot of Verulam formation exposure, which was water worn and mostly just abundant crinoid bits.

[Kane]

On day three we went near one of our more productive spots to check out another Bobcaygeon Fm exposure, but it wasn't the right material. Pictured here is a giant coral and an Isotelus fragment. We retreated to our first productive spot to give it more attention.

[Kane]

1. A half pygidium of what we figure is a Sceptaspsis lincolnensis, which is similar to Calyptaulax.

2. A fragment of the rare Bufoceraurus bispinosus that will be much nicer once I give is some abrasion.

3. Another Bathyurus (Raymondites) longispinus, this time a glabella with a broken occipital spine.

[Kane]

1. Either a Ceraurinella trentonensis or "Xylabion" -- either of which are rare. 

2. On a plate with the same species above as sporting just a cranidium, you need very good ideas to spot this one. The glabella itself is smaller than a pinhead, but here is the cephalon (partially buried) with genal spine of Sphaerocoryphe robusta. Or perhaps it is Physematapsis pernododusus? I am having trouble finding good images of this rare encrinurid, and if it would have had such a long genal spine. @piranha? 

3. I can't say I've ever encountered an Ordovician rostroconch until this trip.

[Kane]

Investigating a road cut and associated rock pile in the Bobcaygeon Fm, Isotelus sp. hypostomes. 

[Kane]

The rock pile had variable lithology, alternating between layers with abundant crinoid stems or just crinoid segments, sometimes being muddy or hummocky, with just brachs, or a combination of abundant crinoids and bryozoans. I didn't take photos of all the rock types, but here are a few:

[Kane]

One of our field comrades inspecting a large slab of long crinoid stems hunting for a calyx, and a closeup of a small section of that slab:

[Kane]

1. What appears to be a big sponge of some sort.

2. A battered Bumastoides.

3. Likely a Flexicalymene senaria pygidium, but maybe not.

4. Possibly a Gabriceraurus dentatus missing its pygidium.

[Kane]

1. One of my field comrades came away with a lot of good crinoid material, and this was just one of them. 

2. A Gabriceraurus dentatus pygidium beside a ventral Bathyurus glabella.

3. The only crinoid I picked up, and it appears on both sides of this sliver of rock.

4. A piggy pile of Isotelus parts in the arenaceous layer where they liked to congregate.

[Kane]

Some bryozoans. Only one of them we know for certain (the second photo) is the rare Constellaria, and the others I have no clue about (but picked them up in the hopes they might be). 

[Kane]

This was going to be the trip-maker for me, the very rare edrioasteroid Thresherodiscus ramosus. One of our comrades was able to find a Foerstediscus grandis.

[Kane]

But my real trip-maker was this: a ventral Dolichoharpes dentoni. Harpids are very rare and prized in Ontario. I stabilized it in the field and will be filling it with ground matrix / glue, mounting it on matrix, and prepping it dorsally. It is not complete, but even finding fragments makes for a trip to remember.

 

In all, I may have added about 10 or so new species to the collection, and I think we all did reasonably well despite some disappointments and less than optimal material at times. We made some incredible memories. I returned home filthy, scruffy, and a bit worn out and I wouldn't have traded this experience away for any other.

[FossilDAWG]

Excellent finds, and an excellent time was had by all it seems.

Hopefully your companion(s) will also post some of their finds.  I'd love to see some more crinoid/echinoderm material.

 

Don

[Fossildude19]

Congratulations on the great strides made in finding productive spots, Kane! 

Sounds like it was a blast!

 

[Nautiloid]

Wow! So many great finds. Congrats on the harpid!! 

[Malcolmt]

Looks like you had an amazing adventure.....put a lot of miles behind you and made some incredible memories

 

[Kane]

Thanks, all!  

2 minutes ago, Malcolmt said:

Looks like you had an amazing adventure.....put a lot of miles behind you and made some good memories

 

I sure did. I couldn't have done it without my two amigos. 

[JohnJ]

33 minutes ago, Kane said:

But my real trip-maker was this: a ventral Dolichoharpes dentoni. Harpids are very rare and prized in Ontario. I stabilized it in the field and will be filling it with ground matrix / glue, mounting it on matrix, and prepping it dorsally. It is not complete, but even finding fragments makes for a trip to remember.

How long did you search for the missing pieces?

 

34 minutes ago, Kane said:

I returned home filthy, scruffy, and a bit worn out and I wouldn't have traded this experience away for any other.

 

Success!