Adam's Ordovician.

[Tidgy's Dad]

This is a coral sent to me by the Heavenly Herb. @Herb

It is from the (Preachersville Member?) of the Drakes Formation of Versailles, Kentucky, USA and is thus Upper Ordovician.

It's a beautiful thing, tentatively labelled "Favosites sp." in inverted commas as it seemed uncertain. 

I have been doing some research, however, and am now leaning towards it being, not from the Favositida, but from the Sarcinulida, which is great, as i really just wanted an U. Ord Tabulate and this is a new group of them for me, I think. So, I reckon, based on the size and shape of the colony ans corallites put particularly based on the enormous calyces, as well as faunal lists for the formation, that this is Foerstephyllum vacuum. 

To make it even more exciting there are bryozoan bits on the underside, and ,even better, several tiny brachiopods, probably Zygospira, but more on those when I've done a bit more work and study and got some decent pictures of them. 

This colony is 7 cm long, 5 cm wide and about 3.5 cm deep.

The individual calyces are up to 6 or in one instance 7 mm across which is pretty huge for a tabulate. 

I love it, thanks Herb!  

[FossilDAWG]

Have you got a photo?

 

Don

[Tidgy's Dad]

7 minutes ago, FossilDAWG said:

Have you got a photo?

 

Don

Several. 

But the dratted things aren't loading (yes, well within my size limit) 

Just trying again. 

There they go! 

[FossilDAWG]

I suspect what you have is a Favistina stellata (Hall).  This species has large corallites (5-6 mm in diameter) and long septa.  In contrast Foerstephyllum vacuum has 3-5 mm corallites (sometimes slighly larger).  The main difference is that in F. vacuum the septa are sparse and reduced to short spines.  See here for more discussion.  Your specimen clearly has well developed septa, which favors F. stellata and excludes F. vacuum.

Note that in her papers on Cincinnatian corals, Ruth Browne did not accept Flower's new genus Favistina, and called the species Cyathophylloides stellata.

 

Don

[Tidgy's Dad]

Thank you, Don! 

I did study this paper, though perhaps not closely enough. 

21 minutes ago, FossilDAWG said:

I suspect what you have is a Favistina stellata (Hall).  This species has large corallites (5-6 mm in diameter) and long septa.  In contrast Foerstephyllum vacuum has 3-5 mm corallites (sometimes slighly larger).  The main difference is that in F. vacuum the septa are sparse and reduced to short spines.  See here for more discussion.  Your specimen clearly has well developed septa, which favors F. stellata and excludes F. vacuum.

Note that in her papers on Cincinnatian corals, Ruth Browne did not accept Flower's new genus Favistina, and called the species Cyathophylloides stellata.

 

Don

I'd be very happy with Favistina stellata, as it is much more uncommon than Foerstephyllum,  only two fragments from one location were found in any of the collections, no complete ones like this! 35 specimens of Foerstephyllum colonies were found by contrast, including Foertephyllum vacuum magnum (which I'm going to guess may possibly have larger corallites?) Do you think it possible that the septa shown here are not just part of the "extremes in a morphologically variable species" , or the short "amplexoid' septa "extending nearly to the axis on the upper surface of the tabulae" ? 

I'm not entirely sure what the amplexoid bit means, to be honest, any help would be much appreciated. 

Thanks again, it's difficult when you've only got the one specimen and nothing else to compare to it. 

[TqB]

11 hours ago, Tidgy's Dad said:

 

I'm not entirely sure what the amplexoid bit means, to be honest, any help would be much appreciated. 

 

It just means the septa are short except where they extend towards the axis on the top surface of a tabula. As in the rugose Amplexus.

From Edwards & Haime, you know the one:

 

 

 

[Tidgy's Dad]

3 hours ago, TqB said:

It just means the septa are short except where they extend towards the axis on the top surface of a tabula. As in the rugose Amplexus.

From Edwards & Haime, you know the one:

 

Thanks, Tarquin! 

[Tidgy's Dad]

Horn corals are very interesting things. The tabulate corals originated quite early in the Ordovician but the rugose corals, beginning with little horn corals appeared much later. A couple of specimens are reported from Iran from near the top of the Middle Ordovician, there are a couple of dubious US ones, supposedly from the very top of the M. Ord,  but most of the earliest certain finds seem to be from the USA and Balto-Scandinavia about 457 million years ago in the early Upper Ordovician. 

They are not supposed to have evolved from a tabulate ancestor, but from a soft-bodied anemone like anthozoan which started to secrete a skeleton for itself. 

The earliest ones in the USA included Palaoeophyllum,  Favistina, Lambeophyllum and Streptelasma, so they were already quite established and there must be earlier forms to be found ; the 'common ancestor' among them. About 453 million years ago, other genera appear in the US, namely Brachyelasma, Grewingkia and possibly Coelostylis. 

Now, I mention all this, not just because it's very interesting, but because a while back I was sent a lovely collection of fossils from Mike @minnbuckeye and among them were 6 little horn corals. I was more excited about the brachiopods and gastropods and things, and never gave these little white calcite specimens much of a thought, got caught up in the world cup stuff and then have been concentrating on Wenlock sponges and tabulates and the Ordovician tabulate Herb sent me. But moving on to my Wenlock horn corals, I suddenly remembered the ones from Mike. 

Ordovician, okay, I have a Streptelasma from the top of the Upper Ordovician I found in the English Lake District, old indeed for a horn coral, but looking at Mike's notes I came to realize that these were older and therefore nearer to the very beginning of the group. 

"Decorah, Iowa" and "Galena, Ordovician".  

The size and shape of them rules out some of the candidates, and the lack of preserved septa is a barrier to id, but the size and shape of them eliminates some of the candidates, so I think these could be Lambeophyllum profundum, Streptelasma corniculum or  Grewingkia canadensis. The biggest one is 2.2 cm high and has a maximum width at the top of 1.4 cm , the smallest one is 1.2 cm high and the same width at the top. 

Here they are : 

  

Thanks a million, Mike! Fascinating. 

[minnbuckeye]

Like I said, if you would want some from the Platteville and Decorah Shale of the Ordovician, let me know!!       Mike

[Tidgy's Dad]

14 hours ago, minnbuckeye said:

Like I said, if you would want some from the Platteville and Decorah Shale of the Ordovician, let me know!!       Mike

Yes, please, anything Ordovician would be great! And these early Rugosa are just fascinating. 

[Tidgy's Dad]

I think I've got it! 

The Galena Formation in Minnesota consists of the Cummingsville, Stewartsville and Prosser members, which I'm vaguely familiar with, but in Iowa it's called the Galena Group and contains the Dunleith and Wise Lake Formations. The fossil horn corals seem to be found only in the Dunleith Formation and are Streptelasma corniculum.

I think. 

[piranha]

The Galena Group also applies in Minnesota.  Cummingsville, Prosser, Stewartville are formations within the Galena Group.

 

[Tidgy's Dad]

20 hours ago, piranha said:

The Galena Group also applies in Minnesota.  Cummingsville, Prosser, Stewartville are formations within the Galena Group.

Thanks, they've upgraded them. 

In Iowa it has added a couple of formations to what I found listed, which complicates matters still further.

https://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=IAOg%3B0

[Tidgy's Dad]

The very kind @DanKurek has marvelously sent me some Ordovician graptolites. 

Firstly, this lovely Isograptus victoriae maximo-divergens from the Bullengarook Slate Quarry, Nr. Gisborne, Victoria, Australia.

It's Castlemainian, CA4 in age which seems to be about 470 million years old and thus Lower Llanvirn which is lowest Middle Ordovician.

There are a couple on the piece. 

Thanks, Dan, they're great.

(and I've nicked one of your photos, too, hope you don't mind! ) 

[Tidgy's Dad]

Also from the mighty @DanKurek is this rather lovely specimens of Didymograptus extensus. 

This is from a slightly earlier time, the Bendigonian , Arenig, Lower Ordovician and about 475 million years old. 

It's an enormous graptolite,  the specimen is 5.2 cm long, but you can see nema at the point of the kink and the right half, as far as is preserved is 4 cm long, double that is 8 cm and add a bit, so that this creature was probably 9 cm plus! 

[Tidgy's Dad]

And another one, this is only a broken partial stipe, but due to the length, breadth and shape, I'm pretty sure this is D. extensus too.

Thanks again, Daniel! 

@DanKurek

[Tidgy's Dad]

This block is most excellent. 

Again from Bendigo, Victoria, Australia and from @DanKurek

It contains at least three species of graptolite. 

The whole block is 8 cm by 7 cm at it's maximum.

There are a couple of partial specimens of Didymograptus extensus, the one below is 1.1 cm long and shows the kink with nema clearly preserved. 

[Tidgy's Dad]

And secondly, Isograptus caduceus victoriae. 

Which goes nicely with the slightly younger Isograptus from Bullengarook shown a few posts back. 

This one's 6 mm across. 

[Tidgy's Dad]

Finally, my favourite, the beautiful Paratetragraptus approximatus. 

The rhabdosome is 1 cm wide and 8 mm high, the central funicle 2.5 mm. 

Lovely.

 

Thank you once again, Daniel! 

@DanKurek

[Wrangellian]

I like those graptolites... I've seen them around and they're on my "gotta have eventually" list!

Seem to be several varieties there and are used as index fossils for the Australian Ordovician, correct?

[Tidgy's Dad]

Yes, there are other species common there too, and the location, Bendigo gives it's name to the Bendigonian, a part of the Australian Lower Ordovician.

http://www.publish.csiro.au/rs/pdf/RS17007

And more commonly and simply :

But noting that no.3 is now Paratetragraptus approximatus, no.5 is Tshallograptus tridens and no.6 Tshallograptus fruiticosus. 

 

[Tidgy's Dad]

Here is a lovely bryozoan sent to me by the marvelous Lori @GeschWhat. 

It's from the St.Paul's Brickyard, now part of Lilydale Regional Park, St.Paul's Minnesota, the Decorah Shale so Middle/ Upper Ordovician about 454 mya.

I've cleaned it up a bit and think it's Batostoma sp. There are at least 3 species found here and I can't tell which one this is. 

The rocky matrix is too hard to remove in places, but i quite like the fossil still in the hash with other bits of different bryozoan species, a nice brachiopod and bits of crinoid stem. 

The bryozoan is 4.2 cm long (high), up to 3 cm wide and about half a cm thick as it's been a bit flattened, I think.

You can also see a pelmatozoan holdfast on the right hand side here. 

And here : 

 

 

 

 

 

[Tidgy's Dad]

The above were pre or mid_prep, these ones after i'd finished.

 

 

 

[Tidgy's Dad]

Lori also sent me another piece of bryozoan hash from the same location. 

This one contained several species :

I think the grey one with more oval apertures is a species of Stictopora, but as there are about half a dozen species found here, I'm not sure which one. I have cleaned them up a bit so must get around to talking some new pictures. And I forgot to measure them.  Sorry. 

I think the red coloured one is Stictoporellina cribrosa as only the one species is found here, as far as I can find. 

Then there's a sort of paler grey/ beige species which seems to be encrusting form on the Stictopora and has very closely packed zooids. I believe this to be Favositella laxata. 

Here is the reverse of the piece :

Thanks, Lori, @GeschWhat, these are beautiful! 

 

 

[Tidgy's Dad]

These are also from the Decorah Shale, but from Decorah itself, in Iowa. They were part of a marvelous package that marvelous Mike @minnbuckeye sent me. 

I'm not sure exactly what type they are, but trepostomes, I should think.