Adam's Ordovician.

[Tidgy's Dad]

The rest of the rock is largely composed of smashed up brachiopod bits, the most common identifiable one being Eochonetes clarksvillensis. It is not a chonetid, it is a sowerbyellid and thus a strophomenid, but the group is thought by some to have been the taxon from which the chonetids and, through them, the rest of the Productida evolved. 

Here are some less damaged examples, up to 1cm wide : 

From the reverse of the rock : 

 

[Tidgy's Dad]

There are also several large fragments from a bigger, thin shelled brachiopod, which, judging from the size, curvature and thin regular striae, are likely Rafinesquina ponderosa. The bits are up to a couple of cm across. 

Here's an example; 

[Misha]

Hash plates are great, this is some beautiful stuff on there!

[Tidgy's Dad]

1 hour ago, Misha said:

Hash plates are great, this is some beautiful stuff on there!

Indeed. Thank you. 

This one's a small and squished Hebertella, I think. About 2 cm across. 

[Bobby Rico]

A lot great work has gone in this thread. Love your photos of the  brachiopod  and Bryozoans are really interesting to look at. Ralph really sort you out with some wonderful  specimens. He is a really kind person. Cheers Adam for the last hour I spent looking at your thread much appreciated. 

Edited July 22, 2021 by Bobby Rico

[Tidgy's Dad]

3 hours ago, Bobby Rico said:

A lot great work has gone in this thread. Love your photos of the  brachiopod  and Bryozoans are really interesting to look at. Ralph really sort you out with some wonderful  specimens. He is a really kind person. Cheers Adam for the last hour I spent looking at your thread much appreciated. 

I appreciate your very kind comments, Bobby.  I'm very glad that you've been having fun reading through some of these pages. 

Yes, there's been a lot of work in prepping, research and attempted ids, but I've enjoyed every minute. Well, mostly. 

I've done a lot of work particularly on the brachiopods and bryozoa because they are so often not given the attention they deserve, but also because they are so common in parts of the Ordovician and are what I like to collect and people send me lots of them.

Ralph has been brilliant, of course, and has sent me a huge amount of material, but many others have contributed, and I have collected some myself as well as bought and swapped some. 

Meanwhile, here are some more brachiopods from my latest hash. 

First this little one, 4 mm across. I don't know. a bit of Catazyga? Fragment of something else or a youngster? 

Here it is at more of a distance. It is on a raised bit of rock compared to the larger brachiopod in the background. I'm not sure what this one is either. Austinella? 7 mm wide : 

 

And just above the mystery orthids, what looks like a Flexicalymene hypostome but could be a bit of broken crinoid stem :

All resting on layers of shattered Rafinesquina ponderosa.  

 

[Bobby Rico]

6 hours ago, Tidgy's Dad said:

Yes, there's been a lot of work in prepping, research and attempted ids, but I've enjoyed every minute. Well, mostly. 

It is an impressive thread all round. Your hard work in preparing, finding, curating and others who have contributed finds makes this a very enjoyable and educational thread. 

[Tidgy's Dad]

Judging from the brachiopod assemblage in the rock, I'm thinking it's Waynesville Formation. 

There are a few bits of crinoid stem sections and columnals in the piece and they all seem to be from the same couple of species, the articulated sections all from the same species.  

Assuming that this is Waynesville and judging from the thickness of the stem, and the large nodals alternating with smaller internodals, plus the comparatively big lumen and little sign of articulation facets, I'm leaning towards Canistrocrinus typus for this one. 

This piece is 5.5 mm long and 2 mm wide : 

This section is larger and completely free of matrix in the central section. Then I broke it during prep and glued it back together very badly. Sorry. 

But at least it gave me a good look at the articulation facets of the columnals. 2.1 cm long and 3 mm wide.

There were a small number of seemingly isolated ossicles as well. Here's an example; 3 mm across. 

And finally, an ostracod? 2 mm long. 

 

 Thank you so much Debra, @Paleome, it's a wonderful hash. 

[Tidgy's Dad]

Now, a timely return to one of my very favourite locations, even though I have never been there and probably never shall, - the Southgate Hill road cut near  St. Leon, Indiana. 

The strata here are Richmondian, Late Ordovician in age and these next specimens are said to come from the Liberty Formation, which overlies the Waynesville at this site. 

These come courtesy of @connorp who kindly included them along with some other bonus items in with a recent auction win. 

First up a half of a Hiscobeccus capax, judging from the comparatively weak growth lines. 

It's 2 cm wide. 

Interestingly, the interior has a mass of pyrite crystals, which I haven't seen before from this site, several broken brachs with calcite crystals, but not pyrite. Very pretty.

 

[Tidgy's Dad]

Though I already have the species Plaesiomys subquadratus, this is my first from St. Leon, my biggest and my only isolated pedicle valve revealing interior detail. 

It's prepped out pretty well too, apart from a bit of matrix in the interior muscle attachment area that is proving rather stubborn.

Anterior view; the pedicle valve of this species is almost flat. 

Short interarea and triangular pedicle opening : 

Lateral view :

Details of costae ; 

Anterior margin showing growth lines : 

Interior margin showing secondary articulation :

Pedicle opening and teeth:

 

 

 

Edited July 24, 2021 by Tidgy's Dad

[Tidgy's Dad]

I think this very pretty specimen is a juvenile Hebertella occidentalis, sometimes referred to in older literature as H. subjugata which seems mostly to have been synonymized with H. occidentalis today. depending on whether you're a lumper or a splitter. 

It was found in the 'Butter Shale' layer of the Liberty Formation at St. Leon, but may be fallen from a higher level, or dropped from elsewhere as there are no orthids I know of in the Butter Shale, just occasional lingulids.  So it may be Liberty, Lower Whitewater or possibly even Waynesville. 

The specimen is 1.4 cm along the hinge-line.

 

Edited July 26, 2021 by Tidgy's Dad

[Tidgy's Dad]

Most people get down on their hands and knees to search in the "butter shale" layer  for the diminutive trilobite Flexicalymene retrorsa minuens, usually found enrolled. 

And here's my first one!  

Though I didn't have to grovel about in the dirt to get it. Which I would love to do one day. Just a bit of light prepping needed, but couldn't do too much as the exoskeleton is preserved in a delicate, thin whitish layer that flakes off to reveal the black internal mold if you poke it too much, so this is as far as I dare go. Most of the black you see was already revealed when I received the specimen. Twasn't me, honest. 

Mmm. A bit more prep here would be safe, I think :

Here is a photo of the specimen next to a standard Flexicalymene retrorsa roller and a slightly larger Moroccan Flecicalymene ouzregui. 

 

I find it amazing that these are all adults of the same genus.

 

Thanks again to @connorp for the last four specimens pictured.

Edited July 28, 2021 by Tidgy's Dad

[Tidgy's Dad]

I received these four pieces in a competition win from Generous Guy @marguy

These are Upper Arenig, which is Upper Early Ordovician, in age and are from the Causse et Veyran, Hérault, S. France.  It's the Landeyran Formation. 

The two medium sized brachiopods in the bottom two rocks, plus another on the reverse of the top left rock, compare with another two pieces I previously received from the same source. 

Here are the old ones : 

Note the hollow costae. 

When I originally posted these two specimens in this thread, I had the id as Hesperonomia landeyranensis, but comparing these with my new specimens and having found further information on the Landeyran Formation of the Montagne Noir area, I now believe them to be Prantlina desiderata Barrande 1948. I am hoping to get hold of a specimen of Hesperonomia landeyranensis in time for my birthday next month to help confirm, but I believe it to be smaller and longer compared to its width than my specimens.

Here are my new P. desiderata, all five specimens are between 1.5 and 2 cm wide : 

There are other much smaller bits of brachiopod in the rocks, but as they are only a few mm across, I can't tell if they're young P. desiderata or one of the many other orthid brachiopods that occur in the Formation. 

 

 

 

Edited July 30, 2021 by Tidgy's Dad

[Tidgy's Dad]

One of the rocks containing a specimen of Prantlina desiderata, shown in the post above, the rock in the bottom right of the first picture, also houses a smaller brachiopod, preserved in a different colour and quite a bit more elevated, especially towards the beak  It is also has fewer and more widely spaced costae and is smaller at 1.1 cm along the hinge line. 

This one's Paurorthis tadridensis :

I poked the shale for a bit with a pin or two: 

 

Notice the primary and secondary costae : 

Edited August 1, 2021 by Tidgy's Dad

[Top Trilo]

Beautiful Brachiopod, This one is really nice, good job on the prep too.

[Tidgy's Dad]

6 hours ago, Top Trilo said:

Beautiful Brachiopod, This one is really nice, good job on the prep too.

Thank you, Alex, very nice of you to say so, though I did ding it a couple of times, that shale was quite difficult to remove. 

 

This next one is shown in the top left of the first photo in the post before last. It has a specimen of Prantlina desiderata on the reverse that I have already posted a photo of and there is a fragment of another one on the edge of this piece. This specimen is a bit less than half of a valve of a much larger brachiopod and the rest of it is missing so I can't prep it out. it measures 2.3 cm across so the complete valve would be close to 5 cm, I should think. I don't know for sure what it is but the best match in terms of size and ornament that can be found in the Landeyran Formation would seem to be Gonambonites sp.

If it is it's rather interesting as this is clitambonitoid and thus a member of the order Billingsellida, a basal group of the Strophomenata that didn't make it past the Ordovician extinction. Paurorthis, pictured in my previous post, is an early Dalmanelladinid, which went on to become a very successful group of orthids.

Next to the brachiopod fragment was this object. At first I had hopes that it was one of the recently much studied conulariids found in the formation, but, alas, I think, upon closer examination that this is just geological. 

    

 

 

[Tidgy's Dad]

All the rocks show signs of what I think are ostracods. they are reported from the Landeyran Formation, but haven't been formally described yet, as far as I am aware.

The formation used to be known as the Inferior Schists du Landeyran, due to the metamorphosis many of these rocks have endured. here is a side view of one sample showing the minerals :

 

And a layer looing very much a schist. 

 

[Tidgy's Dad]

I mentioned that I had hoped in vain that the weird object two posts back was a conulariid, well you can't see too clearly, but the fossil in the rock top right half a dozen posts back really is. 

It is a bit battered but is Galliconularia azaisi.

Until 2020 it was known as  Eoconularia azaisi, but the species is redescribed in this paper and the new genus created:

Conulariids-France.pdf

This is, quite surprisingly, my very first conulariid, so I am delighted. 

Thanks again to Guy @marguy for this specimen and those in the five or six posts above. 

 

The reverse of this rock contains very interesting geological features :

 

[Tidgy's Dad]

Staying in France for one more specimen, this one's from my friend, the Superhero, Sophie @fifbrindacier 

It's a pygidium of one of the trilobites on my 'must get; Yum Yum' list; Neseuretus tristani from La Dominelais, Ille-et-Vilaine, Brittany. The Traveusot Formation which is of Darriwilian / Middle Llandeilo age. So Middle of the Middle Ordovician, about 460 mya. 

Prepping done by Sophie, I expect. It's in another of the schistose shales prevalent in the area. 

 

Thank you, Fifi! 

[Tidgy's Dad]

This next little bunch were an part of an auction win from King @connorp

Brachiopods from the Mifflin Member of the Platteville Formation, Middle Ordovician from Fennimore, Grant County, Wisconsin.

I've nicked Connor's original photo of the specimens as I am lazy.

The rhynchonellid, top left, is Rostricellula minnesotensis 1.1 cm high and 1 cm wide. It was rather covered in gloopy matrix which is the very devil to remove and, though possible, as I have others of this species and even one from Grant County (see page 10), I only did a bit of prep on it. Actually, looking back at the blurred photos of my other one, I had a problem with gloop back then too.

Edited August 7, 2021 by Tidgy's Dad

[connorp]

41 minutes ago, Tidgy's Dad said:

I'm glad you won this lot, in part because I wanted to send you the larger brach in the middle here. I love them but I am not sure on the ID. I am thinking either Rafinesquina or Strophomena, but I am not positive. Any thoughts?

 

I will add that this species are pretty consistent in size and shape from what I've found. But I have noticed a few much larger (4-7cm probably) strophomenids in the Mifflin, although I don't think I've collected any since they are usually in poor shape.

Edited August 6, 2021 by connorp

[Tidgy's Dad]

20 hours ago, connorp said:

I'm glad you won this lot, in part because I wanted to send you the larger brach in the middle here. I love them but I am not sure on the ID. I am thinking either Rafinesquina or Strophomena, but I am not positive. Any thoughts?

 

I will add that this species are pretty consistent in size and shape from what I've found. But I have noticed a few much larger (4-7cm probably) strophomenids in the Mifflin, although I don't think I've collected any since they are usually in poor shape.

The mystery brach that you sent me is Campylorthis deflecta. I'm going to try to prep it a bit before posting.

The larger stroph that you find is probably Strophomena plattinensis. 

Edited August 7, 2021 by Tidgy's Dad

[Tidgy's Dad]

It's makes so much difference having specimens in hand and more of them. It's one of the reasons I was interested in this lot. 

The Pionodema conradi didn't at all match the single specimen of the species in my collection. They are tiny and mine wasn't. 

Here are the two from this new lot, shown bottom left in the post a couple above. 

This first one is 7.5 mm wide. 

 

The brachial valve is a little squished on one side, but still in good nick. 

 

The second specimen is just 6 mm across.

What I had previously labelled as Pionodema conradi was clearly much to big, even bigger than any of  the Pionodema subaequata that I have from the slightly younger Decorah Shale. 

I now know that this other specimen, pictured on Page 10 of this thread, is actually a Doleroides pervetus, as I now also have this species from the Decorah to compare it against. In my defence I would say that Pionodema conradi is listed as the most common brachiopod in the Mifflin from Illinois and Iowa at least and I didn't have anything else close, and that Doleroides pervetus wasn't in the faunal list I had at that time as it seems to occur in Wisconsin but not Iowa or Illinois. And I hadn't realized how small P. conradi was compared to P. subaequata. 

I often learn by getting things wrong. 

 

Edited August 7, 2021 by Tidgy's Dad

[Tidgy's Dad]

The two specimens on the right of the photo four posts above are Oepikina minnesotensis. 

Here is the smaller specimen measuring 1.7 cm wide, note the geniculation, which is sharply rounded but not angular, and lack of much surface detail.

The brachial valve is concave and buried in matrix which is quite hard and would take too long for me to remove.

The second specimen is 1.9 cm across. Again note the geniculation and very fine costae.

I managed to remove some of the matrix this time. Note the very strophic hinge line. 

 

The geniculation with growth lines only clearly visible on the anterior side of it.  

Since this page in my thread is dedicated to errors made previously, I will refer you again to page 10 of this thread in which my two previous specimens of Oepikina minnesotensis are listed confidently as Strophomena plattinensis. Oh, dear. 

In my defence I have to point out the species was originally classified as Leptaena, then moved to Strophomena, then to Rafinesquina before finally being given its own genus.  So it wasn't just me who was confused. And I didn't have a lot of specimens. And the tell-tale means of identification are internal features, primarily from the brachial valve and I don't have any valve interiors. And much of the info is listed under the name Opikina without th 'e' so I missed some vital info. And I get over-excited.  Other specimens on page ten suffered a knock-on effect because of this. What I had listed as Oepikina minnesotensis is actually presumably O. inquassa from the Decorah Formation, much more sharply geniculate and usually larger with more obvious costae. At least I had the genus right this time. 

I must particularly apologize to my friend Mike @minnbuckeye for the misleading information on page 10. I live (thankfully) and learn. Mike actually posted a thank you on that page, as he'd now be able to identify his specimens more easily. Oops. Sorry, Mike.   Hopefully, this post, the ones above and the next one will help sort out the mess. 

 

There are some interesting things in the gloop stuck to the valve here.

Is this one below an ostracod, quite common in the Platteville, or just a grain of sand? 2mm wide.

It looks round due to the angle of the photo above but is actually oval. See below.

Bryozoan? 

 

 

Edited August 12, 2021 by Tidgy's Dad

[Tidgy's Dad]

The big one, from the top centre of the post of August the 6th above, is Campylorthis deflecta, 2.2 cm wide. 

The species is very similar in looks to Strophomena, but the giveaway is the fold and sulcus in the anterior half of the shell. 

The interarea is full of gloop, unfortunately. 

Thank you so much, @connorp These specimens have helped my understanding a great deal. 

Slowly, I learn.