Adam's Ordovician.

[Wrangellian]

9 hours ago, Tidgy's Dad said:

Thanks, Eric.

Yes, love this hash plate, not just brachys and bryos but crinoid columnals and trilobits too. 

Haven't tried the vinegar on the white scratch areas, doesn't bother me too much, but these shells are easily dissolved in vinegar from a previous test, so i'll leave it. 

Yes, please post your brachiopod when you can, I've been studying the fossils of this region quite extensively so may be able to have a stab at an id. 

I wouldn't use anything too harsh - first I'd try diluted vinegar, or just leave it out in the rain a couple times (but I guess you don't get much rain there!)... Do the fossils exposed at the site become etched after not too long, if no one comes by to collect them soon enough?

I would not think it should take much to dull the whiteness, especially if you precision-applied the dilute acid, unless the fossils were somehow as prone to dissolution as the matrix.

OK, I'll try to get pics and post the one I mention, and a couple others that might be from the same site. Much more sunny daylight hours these days to get some decent outdoor lighting. 

[Tidgy's Dad]

12 hours ago, Monica said:

Adam - your hash plate looks delicious - great find from Ralph, and great prep work by you!!! 

 

I especially like the Leptaena (I'm assuming that's what they are!) brachiopods 

Thank you, Monica.  Ralph certainly did me proud with this hash and specimens from St Leon in general.  

Yes, that's Leptaena richmondensis. Leptaena is one of my favourite genera and very successful, I have it, or the subfamily, from Ordovician, Silurian,  Devonian and Lower Carboniferous strata. 

I'm prepping a couple of others at the moment, but these Leptaena are next. 

[Tidgy's Dad]

There were a couple of species of strophomenid in the hash as well. 

First up were just a couple of specimens of Eochonetes clarksvillensis. 

This species has been through more name changes than someone who changes their name a lot. It was known as Plectambonites rugosa-clarksvillensis, then Sowerbyella clarksvillensis, Thaerodonta clarksvillensis and Eoplectodonta clarksvillensis. Some sites still list it as Sowerbyella sp. 

Anyway, it's smaller than the other species in the block and much more thin shelled and fragile, so suffered a bit of damage before and during minimal prepping.

This first one, right on the edge of the hash, on the right, is 1 cm wide :

The second one is a little bigger, 1.3 cm wide, bottom centre of the rock :

 

 

 

[Tidgy's Dad]

I have another rock from St.Leon, also from Ralph @Nimravis, that is covered with Eochonetes clarksvillensis. The name Eochonetes means 'dawn Chonetes' as this genus, or maybe another genus from the Sowerbyellidae family is thought to have given rise to the later, very successful suborder Chonetidina  and therefore to the whole order Productida, probably the dominant group of brachiopods in the Upper Palaeozoic. 

The scale cube is 1 cm : 

And after a bit of cleaning, mostly with a toothbrush :   

Interestingly, this mortality plate shows the convex surfaces of the pedicle valve exterior and the brachial valve interior only, with one exception; a single concave brachial valve exterior. The animal was concavo-convex. The currents presumably favoured the brachiopods lying with the convex side upwards even with disarticulated valves. 

Some pedicle valve exteriors :

 

 

 

[Tidgy's Dad]

Brachial valve interiors : 

Bit of a mix :

 

[Tidgy's Dad]

The lone concave brachial valve exterior :

And some nice bryozoa :

This one's growing on an Eochonetes valve. 

 

[Tidgy's Dad]

The reverse of this rock is far more barren.

Just a few specimens visible : some bryozoa, tiny crinoid columnals, brachiopod bits and some concave brachiopod valve interiors including some Eochonetes clarksvillensis brachial valve interiors. These are between 1 and 1.3 cm wide.

 

 

 

[Wrangellian]

OK here ya go, my 3 brachiopods from that Cinncinatian area of the Midwest. One of them I know is Leptaena but I wouldn't know which species. I don't know which site or formation these would have come from as that info was lost, if I ever had it. I suspect they all came from the same site, probably one of the big famous productive ones like St. Leon, but I may be wrong in that.

These were all bought from a fossil shop in Drumheller Alberta on one occasion in the 1980s!

Various views of the same 3 specimens:

Hopefully there is enough detail visible to get an idea. If not, I could try for better pics, but it's a bit tricky, hence my delay.

[Tidgy's Dad]

8 hours ago, Wrangellian said:

OK here ya go, my 3 brachiopods from that Cinncinatian area of the Midwest. One of them I know is Leptaena but I wouldn't know which species. I don't know which site or formation these would have come from as that info was lost, if I ever had it. I suspect they all came from the same site, probably one of the big famous productive ones like St. Leon, but I may be wrong in that.

Yes, that's Leptaena richmondensis, actually the species I'm working on right now from my St. Leon hash plate. 

The rhynchonellid, judging from the size, shape and conspicuous growth lines, is a pretty nice example of Lepidocyclus perlamellosum.

The third one is an orthid; Cincinnetina meeki  I think. 

They do all occur at St. Leon, but in other places where the top of the Cincinnatian is exposed as well. 

Nice specimens, thanks for posting.  

[Wrangellian]

Thanks Adam. That mostly jibes with suggested IDs that I was given a while back (I wasn't going to mention that right off the bat because I wanted an independent 2nd opinion! and anyway I can't find that post offhand. It was a while ago, and probably worse pics.) The only difference is that Plaesiomys subquadrata was suggested for the orthid.

Which formations do these species occur in? More than one, I suspect...  When you say "top of the Cincinnatian", does that include the Gamachian as well as the Richmondian? (The Gamachian is the topmost stage on my chart.) In other words, does L. richmondensis occur only in its namesake stage, the Richmondian, or did it have a greater range? (same question for the others)

[connorp]

Ah, I love the Eochonetes mortality plates! I have a couple from my one hour visit to St. Leon last year, definitely some of my favorites.

[Tidgy's Dad]

35 minutes ago, Wrangellian said:

The only difference is that Plaesiomys subquadrata was suggested for the orthid.

Which formations do these species occur in? More than one, I suspect...  When you say "top of the Cincinnatian", does that include the Gamachian as well as the Richmondian? (The Gamachian is the topmost stage on my chart.) In other words, does L. richmondensis occur only in its namesake stage, the Richmondian, or did it have a greater range? (same question for the others)

Firstly, it's Plaesiomys subquadratus, P. subquadrata is a common error. Secondly, I would expect this species to be a bit bigger and far more domed than your specimen and not to have such a prominent medial ridge. However, brachiopod morphological variability is such that I wouldn't rule it out, the species does occur at St Leon.

Yes, I should have specified Richmondian. P. subquadratus occurs only in the Whitewater Formation at St. Leon and the Cincinnati type area,  but does occur earlier elsewhere. Cincinnetina meeki is found in the older Arnheim and Waynesville Formations, Leptaena richmondensis in the Arnheim, Waynesville and Liberty Formations at St. Leon, but also in the Elkhorn in Ohio, all Cincinnatian. Finally, Lepidocyclus perlamellosum occurs in the Waynesville Liberty and Whitewater at St.Leon, plus the Elkhorn in Ohio. 

So, if the three come from the same formation, and it is Cincinnetina meeki, it must be the Waynesville, but if it's Plaesiomys subquadratus the three must come from at least two different Formations, which is possible with loose specimens, of course.  

 

[Tidgy's Dad]

1 hour ago, connorp said:

Ah, I love the Eochonetes mortality plates! I have a couple from my one hour visit to St. Leon last year, definitely some of my favorites.

Yeah,  beautiful and fascinating too. 

[Wrangellian]

2 hours ago, Tidgy's Dad said:

Firstly, it's Plaesiomys subquadratus, P. subquadrata is a common error. Secondly, I would expect this species to be a bit bigger and far more domed than your specimen and not to have such a prominent medial ridge. However, brachiopod morphological variability is such that I wouldn't rule it out, the species does occur at St Leon.

Yes, I should have specified Richmondian. P. subquadratus occurs only in the Whitewater Formation at St. Leon and the Cincinnati type area,  but does occur earlier elsewhere. Cincinnetina meeki is found in the older Arnheim and Waynesville Formations, Leptaena richmondensis in the Arnheim, Waynesville and Liberty Formations at St. Leon, but also in the Elkhorn in Ohio, all Cincinnatian. Finally, Lepidocyclus perlamellosum occurs in the Waynesville Liberty and Whitewater at St.Leon, plus the Elkhorn in Ohio. 

So, if the three come from the same formation, and it is Cincinnetina meeki, it must be the Waynesville, but if it's Plaesiomys subquadratus the three must come from at least two different Formations, which is possible with loose specimens, of course.  

 

OK.. I can't tell if they all came from the same formation, I'm only thinking that, if it's possible for these 3 species to all come from the same site, they probably did, given that they all came from the same shop at the same time, maybe the had the same supplier, but again, I could be wrong. I need to know if there are any other sites than St Leon that would be anywhere near as likely to be a source for these kinds of fossils supplied to fossil shops around the continent in the 1980s.

Anyway, thanks again, I'll go with what you've given me. I can't see much of a medial ridge at all on the orthid, btw, but maybe I'm not sure what constitutes 'prominent'.

[Tidgy's Dad]

I've no idea what was accessible back in the 80's, and here's your rather old thread : 

http://www.thefossilforum.com/index.php?/topic/17393-brachiopods-and-blastoids/&

Parentheses around a name placed between genus and species indicate a subgenus, I understand, but Plaesiomys and Dinorthis are now generally classed as separate genera. 

Your one could be Plaesiomys. I'm certainly not certain! 

[Wrangellian]

There it is. Wow, 2010-11... well I knew it was old. I guess I found it difficult to sort out the info I got but I think I've got it as close as I possibly can now. I've at least simplified the labels. Back in the drawer they go.

I didn't expect you to know what was accessible in the '80s, only suggesting that if I knew that, I might be able to narrow down the source of my 3 items.

Anyway, thanks again. Back to the regularly-scheduled program!

 

[Tidgy's Dad]

So, here is the last species of brachiopod from my St. Leon hashplate. 

Leptaena richmondensis,.

Lovely.

Here is a pedicle valve in the centre of a nice grouping of brachiopods, 2.1 cm  wide :

And a close up :

Bit blurred, so here's a couple using the digital microscope :

And a couple of brachial valve interiors, the biggest one, top left, is2.7 cm from ear to ear :

You can see the teeth for articulation, the muscle scars and a medial ridge. 

You can also see the tiny bumps which are typical of the inside of strophomenid valves and are also visible in the close ups of Eochonetes shown above. 

 

 

 

 

 

[Tidgy's Dad]

Still from the Cincinnatian of St. Leon are these wonderful Rafinesquina alternata. 

Pedicle valve : 

This species is smaller on average than R. ponderosa, and also not nearly as flat, as can be seen from this anterior view: 

Note also that the side view reveals the wedge shape showing the family resemblance with Leptaena :

 

 

[Tidgy's Dad]

The second specimen, another pedicle valve : 

On the reverse of this specimen is half a concave brachial valve : 

And a tiny Zygospira modesta. 

 

 

 

[Tidgy's Dad]

Finally, this one's the interior of the brachial valve with some nice detail despite some damage :

[FossilNerd]

Nice Rafinesquina Adam! They are found in some of the Ordovician spots that I have hunted, but alas, I have not found any decent specimens. They are not nearly as common as Vinlandostrophia or Hebertella are in those areas.

 

It's always nice to find a decent enough valve to see the interior structure. I have a couple, but they are mostly out of the matrix and are very delicate.

[Tidgy's Dad]

21 hours ago, FossilNerd said:

Nice Rafinesquina Adam! They are found in some of the Ordovician spots that I have hunted, but alas, I have not found any decent specimens. They are not nearly as common as Vinlandostrophia or Hebertella are in those areas.

 

It's always nice to find a decent enough valve to see the interior structure. I have a couple, but they are mostly out of the matrix and are very delicate.

Thanks. 

I'm lucky enough to have a few Rafinesquina from several different locations, but this is the only one which is an internal valve. I guess their articulation was pretty good so they don't separate as often as some other species, or once they're separated they're so fragile they just break to bits. 

[FossilNerd]

10 hours ago, Tidgy's Dad said:

Thanks. 

I'm lucky enough to have a few Rafinesquina from several different locations, but this is the only one which is an internal valve. I guess their articulation was pretty good so they don't separate as often as some other species, or once they're separated they're so fragile they just break to bits. 

I think your guess is spot on.

I really need to take a day/weekend trip and head north. Hit some of the classic spots like St. Leon and Maysville. So close, yet so far away... 

[Tidgy's Dad]

7 hours ago, FossilNerd said:

I think your guess is spot on.

I really need to take a day/weekend trip and head north. Hit some of the classic spots like St. Leon and Maysville. So close, yet so far away... 

It seems these localities are well worth the trip. Add on the Lawrenceburg road cut as well and I'd be in Paradise. You'd never be able to drag me away! 

[FossilNerd]

1 hour ago, Tidgy's Dad said:

It seems these localities are well worth the trip. Add on the Lawrenceburg road cut as well and I'd be in Paradise. You'd never be able to drag me away! 

Oh yes, and Lawrenceburg! 
 

I know right?! It would be an epic time and I would definitely find it hard to leave! I will get up to one of them (or all) some day soon, after the world gets back to some sort of normality. I’ve been talking to my wife about a day trip to hunt one of them. When I do, you will have a gift box coming your way!