2020 Ontario Trilobite Hunting

[Kane]

I've been fairly active in trying to prospect new spots. Of course, most of those will turn up to be false/dead leads.

We hit two locations today that were fairly useless. On our way back we stopped at one place for the view. Among the strewn stuff were some ok things, such as this group of Leptaena and these neat gastropods...

[Kane]

But that was not going to be the winning spot. I spied something in the distance, which had such an abundance of material that I was truly overwhelmed. at first it was just brachs...

[Kane]

And this one rock, a slab about a metre wide and long, and about 50 cm deep, was so full of brachs that it seemed more brach than matrix.

And some of them were huge. 

Oh, and rostroconchs. Zillions of them. 

[Kane]

But this thread is about the trilobites! 

In this same rock was a bug bonanza.

Four species in the same rock.

And there is an incredible abundance of this material to get through... Out of the thousands of these rocks, I managed to get through just one. 

 

First of the four, and the most significant, Coronura aspectans Check out its pygidial “spokes”! 

EDIT: in hindsight, after having a look at the plates in TONY, this may seem a better match for C. helena rather than C. aspectans. I'll have to page our Dr. Trilobite to give his diagnosis... @piranha

 

[Kane]

Of course, Pseudodechenella would appear quite often in this stuff, but so too did Anchiopsis anchiops:

[Kane]

The fourth species was only fragmentary, but hardly common in Ontario: frontal lobe denticle/margin of Odontocephalus sp. Two examples!

[Kane]

Now, keep in mind this is just a single slab out of many thousands. This markup of an image from Lesperance and Bourque's paper indicates the three I found together cohabiting the same slab. I am over the moon!

 

I will definitely be going back there again. Soon!

 

[Fossildude19]

Congratulations, Kane! 

Who knows what the future holds there...  

[piranha]

2 hours ago, Kane said:

EDIT: in hindsight, after having a look at the plates in TONY, this may seem a better match for C. helena rather than C. aspectans. I'll have to page our Dr. Trilobite to give his diagnosis... @piranha

 

 

Coronura helena has weak to obsolete pygidial tubercles.  Because of the weathered preservation, I can't tell one way or the other  

[Kane]

Thanks, Scott! I suppose that means I’ll have to find a better specimen! 

[FossilDAWG]

Great news!  The preservation of some of those is quite nice too!

 

Don

[Monica]

The pygidium for Anchiopsis anchiops is beautiful! 

[Kane]

On 2020-04-01 at 6:03 PM, Fossildude19 said:

Congratulations, Kane! 

Who knows what the future holds there...  

Aye, and that is what is truly exciting. I've barely scratched the proverbial surface. It's Onondaga time!

 

On 2020-04-01 at 8:46 PM, FossilDAWG said:

Great news!  The preservation of some of those is quite nice too!

 

Don

Thanks, Don.  Some do come out quite crisp in detail while others, like the gastropods, only appear as steinkerns. 

On 2020-04-02 at 5:24 AM, Monica said:

The pygidium for Anchiopsis anchiops is beautiful! 

Thanks.  It certainly matches the handful I've found of this species in imported fill here in town, but that dried up a few years ago. The prospect of finding a complete example of this splendid dalmanitid is certainly worth many return trips. But, so too the other species, one of which has not been reported in Ontario since 1915 (Odontocephalus sp), which can join the few other species I've found in the last six months that have never been reported here, and only in equivalent strata. 

[Tidgy's Dad]

Nice finds and certainly bodes well for the future.

One quibble :

15 hours ago, Kane said:

 it was just brachs...

[Shamalama]

Great finds as per ususal Kane. Glad you found a new spot to explore. You will get that complete Acanthopyge contusa eventually.

[Kane]

On 2020-04-02 at 8:03 AM, Tidgy's Dad said:

Nice finds and certainly bodes well for the future.

One quibble :

Sorry, I should correct that: "it was just spectacular brachs."  I did take those big ones home instead of allowing the forces of nature to reclaim them. And, to be honest, I've never encountered so much diversity of brachiopods -- never a dull split!

On 2020-04-02 at 8:14 AM, Shamalama said:

Great finds as per ususal Kane. Glad you found a new spot to explore. You will get that complete Acanthopyge contusa eventually.

I do hope so! Looking over the faunal inventory of the Onondaga, it is quite lengthy and includes a few lichids. 

[FossilNerd]

 

14 hours ago, Kane said:

This markup of an image from Lesperance and Bourque's paper indicates the three I found together cohabiting the same slab.

 Looks like you hit the jackpot! If all of this was from one slab out of thousands, and if it’s an indication of what’s to come, you are in for a real treat! 
 

Congrats on the great multi-block and the new, very productive, hunting grounds!  

[Kane]

Thanks, Wayne! I am positively giddy with anticipation. I may go back again tomorrow (and Saturday, if my missus is willing). 

[Kane]

Although this will not assist in drilling down to species level due to the pitted and weathered preservation of this specimen, it looks a bit better now that I've done some light scribing to reveal the spokes on the right side.

 

Pygidium is 4 cm long and about 5 cm wide (but truncated on the right side). It would have belonged to a specimen of about 10 cm, which is nowhere near the absolute limit for Coronura aspectans, with some recorded as being up to 50 cm long -- by far the biggest dalmanitid in this strata. 

[fifbrindacier]

22 hours ago, Kane said:

But this thread is about the trilobites! 

In this same rock was a bug bonanza.

Four species in the same rock.

And there is an incredible abundance of this material to get through... Out of the thousands of these rocks, I managed to get through just one. 

 

First of the four, and the most significant, Coronura aspectans Check out its pygidial “spokes”! 

EDIT: in hindsight, after having a look at the plates in TONY, this may seem a better match for C. helena rather than C. aspectans. I'll have to page our Dr. Trilobite to give his diagnosis... @piranha

 

 

22 hours ago, Kane said:

Of course, Pseudodechenella would appear quite often in this stuff, but so too did Anchiopsis anchiops:

Awesome Kane, that pygidium is wonderful. The size of those brachs is stunning.

[Kane]

Thanks, Sophie!  I hope to add more tomorrow!

[fifbrindacier]

I'll wait with great impatience.

[Kane]

Spent the better part of two days in my Onondaga material. Not every rock is filled with fossil riches, as I have discovered; some are blank + sandy or blank + cherty, and otherwise brutally hard to bust. Others are enormous sheets of brachiopods or even entire planes of rostroconch. 

 

Anyway, B is for brachiopod. The diversity is very high, so I am selective in what I bring home. A snap of what are about crabapple-sized ones, plus a typical brach-infused bedding plane with a large spirifer.

 

 

[Kane]

Rostroconchs galore + gastro steinkerns (and one tiny brach with both valves -- I pocketed a few of these if they were intact). But have a look at those large rostroconch. For as much as these are a bit of a nuisance in my layers, I was impressed with these ones.

[Kane]

Occasionally one encounters semi-hollow vugs with some lovely calcite crystal formation. Next to this battered rostroconch is some nice crystals.

Also picked up this oddball, which is likely a stromatoporoid with very pronounced mamelons. 

And, just to give an indication of how numerous the rostroconch can be, see how many you can count on this rock!