Adam's Mid Devonian - Eifelian

[Tidgy's Dad]

I am fortunate enough to have such a huge amount of Middle Devonian Givetian material that I thought it best to put the older Middle Devonian stage, the Eifelian, in its own thread.

There are some spectacular fossils here as well though!

I thought a good place to start would be in the Formosa Reef, which I believe is quite early Eifelian. This tabulate coral and  stromatoporoid reef continues similar complexes found from the Middle Silurian, see my:

https://www.thefossilforum.com/topic/84678-adams-silurian/page/3/ 

thread from page three onwards for details.

All these Formosa Reef specimens come from a delightful gift from my good friend @Monica who is a tad busy with life at the moment but is fine and still thinking of the forum.

This outcrop can be found on Route 12 near Formosa/Amherstburg, Bruce County, Ontario, Canada.

This beautiful-looking specimen came to me with only a third of it revealed but I managed to get it this far after nine days of painful pin prepping.

Monica found another one and posted it for ID here:

https://www.thefossilforum.com/topic/105528-weird-circular-imprints-formosa-reef-lower-devonian/#comment-1172285

The specimen was identified by another Canny Canadian @Kane to be the little stromatoporoid sponge Syringostroma cylindricum.

Hardly a reef-builder, but gorgeous nonetheless.

It does have a little thickness to it, but not much.

Beautiful!

Pretty thin, actually.

I love this Monica, thank you!

Edited January 26 by Tidgy's Dad

[Tidgy's Dad]

Looking into the reef in more detail it seems that stromatoporoids were quite abundant, varied and the major part of the reef builders in the Formosa Reef.

Some of these are massive and some thinner layers like this one,

It is quite thin, not as noticeably layered as some, and has irregularly spaced mamelons with conspicuous astrorhizae, so I believe this to be a sample of Stictostroma longitubiferum.

The tops of some of the mamelons have been chipped or eroded off and the astrorhizae are quite clear.

Here is a longitudinal view. It is only a thin layer in the top of the rock.

 

 

Close up of the mamelons and astrorhizae:

Under maximum magnification, there is some evidence of the pillars in the cross-section.

Edited January 30 by Tidgy's Dad

[Tidgy's Dad]

There are some pretty large tabulate corals in the Formosa Reef and I have seen some huge chunks of the favositid Emmonsia posted on the forum and elsewhere, Yummy.

I'm not sure about this one. It looks a bit like a rather bashed about Syringopora and the species Syringopora hisingeri occurs at this location, but I can only see many sign of the connecting canals though this species doesn't seem to have as many as some.

The tubes are not as thick as they look as they are coated in places by calcitic gloop.

 

I think I see some evidence of connecting canals in the photo below.

 

Edited February 2 by Tidgy's Dad

[Tidgy's Dad]

There are a fair few rugose corals in the Formosa Reef too.

The Amherstburg Formation lists some lovely phaceloid genera and a lot of quite small horn corals.

This one is tiny, only 3mm wide at the calyx and 8mm tall.

Placophyllum and Depasophyllum seem close but I have also seen both of these synonymized and placed in Synatophyllum.

Making this possibly Synatophyllum tabulatum.

But this really is guesswork, I don't honestly know.

Is this "tongue" bit a part of the calyx sides that have otherwise been broken off?

More bits of those tubes next to it.

Syringopora?

 

 

 

 

Edited February 6 by Tidgy's Dad

[Tidgy's Dad]

Another horn coral from the Formosa Reef.

Much bigger but poorly preserved and not showing any of the septa.

Probably a stauriid, perhaps Heliophyllum or Heterophrentis?

[Polybranchiaspidida]

Although I don't collect coral fossils what I want to say is that it's really beautiful.

[Tidgy's Dad]

On 2/11/2024 at 6:50 AM, Polybranchiaspidida said:

Although I don't collect coral fossils what I want to say is that it's really beautiful.

Well, thank you very much for saying so, but I don't think it's up to much, to be honest. I like it when they are free from the matrix and showing the septa, like this one.

Grewingkia canadensis, Late Ordovician from Garr Hill, Indiana.

I have some nice Devonian ones to come later.

Meanwhile, I do think this bryozoan growing on the horn coral that you liked from the Formosa Reef in the last post is pretty.

Probably an encrusting Fistulipora sp. which does occur in the Amherstburg Formation at this location, but I don't think the species have been described.

[Tidgy's Dad]

This one was a very pleasant surprise.

I am not certain, but this looks very much like an inarticulate brachiopod to me. And I can find nothing relating to inarticulates in the Formosa Reef/ Amherstburg Formation literature or faunal lists. @Kane Have you ever noticed anything similar in your visits to the Formosa roadcut, old chap?

I think maybe it is Craniops sp. but as I am afflicted with brachiopod pareidolia, I am open to other, less biased suggestions. 

It is 1.2 cm long.

Note the beautiful fine striae.

 

[Kane]

Can't say that I have, but I do confess that I don't pay as much mind to these in my zealous hunt for trilobites.  

[Tidgy's Dad]

On 3/15/2024 at 12:30 PM, Kane said:

Can't say that I have, but I do confess that I don't pay as much mind to these in my zealous hunt for trilobites.  

Ha ha.

I thought you might answer along those lines, though I have seen excellent fossils of other critters you,ve picked up at the Fornosa Reef roadcut  over on your blog, rostroconchs for example. Thanks for looking. 

 

I have read that Pentamerella pavilionensis is one of the more common brachiopods to be found in the Amherstburg Formation. But I have only found one partial in my rock samples. Still, it's nice to have a Middle Devonian pentamerid as the order is in decline by this time and will soon become extinct during the Kellwasser Event in a few million years time.

It's very small at 8 mm wide. 

 

Pentamerella grandis is a larger species found in the formation but is rare and only known from isolated brachial valves. 

[Tidgy's Dad]

Two species of "Atrypa" are recognized from the Amherstburg Formation, Atrypa sp. A and Atrypa sp. B. Hmmm. With nothing in the way of internal morphology and much more work needed to be done on the Middle Devonian Atrypida, it is not known if one of these species is A. reticularis or if they are both new species. As the atrypids had their greatest surge of evolutionary divergence in the Middle Devonian with a whole new batch of genera and species recorded, the waters are muddied still further.

The larger of the species, Atrypa sp. B is the more common in the Formosa Reef, the most similar to A. reticularis, and is what I think I have here.

1,8 mm wide.

I think that this fragment may also be Atrypa sp. B, it doesn't seem to fit any of the rhynchonellids in the formation.

[Tidgy's Dad]

This is Kozlowskiellina submersa, 1.2 cm wide.

The Treatise has this genus limited to the Silurian but this Devonian form used to be known under the subgenus Megakozlowskiellina which has been synonymised with Kozlowskiellina since the last Treatise update, thus increasing the range of the genus well into the Devonian. Megakozlowskiella is still recognised as a separate genus.

This is nice as I have Kozlowskiellina strawi from the Wenlock of England and Kozlowskiellina perlamellosa from the Early Devonian Birdsong Shale. of the USA. Now this one from the Formosa Reef, Amerstburg Formation of Canada. Good to have a genus from three different times and three different countries.

 

 

[Tidgy's Dad]

A weakly ribbed spiriferid Elita formosensis. ( was Elytha formosensis and then Elyta formosensis )

Also from the Formosa Reef, Amherstburg Formation.

[Mark Kmiecik]

What are the dimensions of this specimen?