Adam's Ordovician.

[Tidgy's Dad]

This next one's a corker! 

A lovely domed colony of Prasopora simulatrix, also from the Decorah Shales, Decorah, Iowa. 

I just love this specimen.

Thank you so much, Mike @minnbuckeye

[Tidgy's Dad]

This one's rather a mystery. 

It was also sent to me by Mike, but this one's from the Platteville Formation, Fillmore County, Minnesota. 

It's pretty enormous, maybe four inches across, and looks to me the right size and shape for Prasopora grandis, which would fit the formation and location. 

But it came to me tentatively labelled as stromatolite/ lith ? 

I'm actually not sure it's either as it has no sign of internal structure, other than some layering, but nothing vertical. Lots of fossils here suffer from dolomitization so the internal structure may be lost, but why does this still have horizontal layering? Just a sedimentary structure of some kind? 

 

 

[Bobby Rico]

Fantastic photos have you got a new camera? I just a had a look at your Norwegian material I think a page 1 beautiful form a beautiful place.

[Tidgy's Dad]

On 10/18/2018 at 12:07 PM, Bobby Rico said:

Fantastic photos have you got a new camera? I just a had a look at your Norwegian material I think a page 1 beautiful form a beautiful place.

Hi, Bobby! 

No, just getting used to wifey's camera phone and using it with a loupe, I think. 

But thanks for your kind remark. 

[Tidgy's Dad]

A while back, I was sent some rather wonderful bryozoans from the roadcut near Lawrenceburg, Indiana by the always super generous Ralph. He was just supposed to be sending me some Constellaria to replace one i'd lost, but being Ralph, he sent me several others including this little lot :

The longest piece (top right) is 5.7 cm long. 

They are from a rich bryozoan fauna , Upper Ordovician, probably Maysvillian and i think the Fairview Formation, Fairmount Member and probably the Hawk-Gillespie and / or Lawrenceburg, submembers judging by the fauna from the location I have or have seen. 

I will start with the bottom left specimen, labelled 'b' if I may. 

Bryozoans are just as difficult to identify without cross-section as corals, but judging by the diameter of the branches, the look of it under a loupe , the breaks , the anastomising (branches rejoining) and the clear monticules it is Parvohallopora, a common genus here, most of the the genera previously assigned to Hallopora and others have been reassigned to this genus. It does not have the sharp spikes of P. ramosa nor the ridges of P. rugosa, so is likely to be Parvohallopora subplana (I think!) 

Thanks, Ralph. @Nimravis It's a beautiful piece. 

[Bobby Rico]

They are really great specimens 

[Tidgy's Dad]

On 11/2/2018 at 11:30 PM, Bobby Rico said:

They are really great specimens 

I think so too. 

This one, 'c' in the photo above, is another trepostome, and judging by it's frondose shape, with a concave side, crease, arrangement of zooecia and weak monticules could possibly be Heterotrypa subfrondosa. Happy for any other ideas. 

 

Thanks again, Ralph! @Nimravis

[Tidgy's Dad]

The two labelled 'a' are also trepostomes, I think they're likely to be Amplexopora septosa, due to the seeming smoothness, yet obvious monticules when you look, thin and sharply branching structure and very clear bifoliation. 

Again I am interested in any other opinions. 

• Drag files here to attach, or choose files... 
  Max tota

And again, Ralph, @Nimravisthank you very much. 

Off Notify me of replies

 

[Tidgy's Dad]

There are a shed load of bryozoans to be found in this particular strata, encrusting, ramose, frondose, massive, domed............Loads od different genera and even more species. 

Fascinating stuff, a bryozoan reef , before corals had really 'taken off' with brachiopods galore lurking within, as will be seen,and  orthocones as predators. 

But I have one more thanks to Ralph, the one I wanted in the first place, a replacement for my missing specimen, though this is a different species, it is a more than worthy substitute, couldn't ask for more, the marvelous and very, very beautiful Constellaria florida. 

The zooecia are particularly tiny in this species. 

Beautiful, gap in collection filled. 

Thanks once more, @Nimravis

 

 

 

[TqB]

Gorgeous, Constellaria is on my wants list too.

[Tidgy's Dad]

As promised, the marvelous, magnificent, mighty Mike from Minnesota @minnbuckeyeposted me some even older solitary rugose horn corals from Decorah, Iowa.

He even sent me colour satellite images of the locations of both these groups of corals. 

These are from the Platteville Formation so a couple of million years older than the last batch at about 454 mya. 

The corals are quite a bit bigger than the other ones; up to 2.7 cm tall and and 2 cm across at the top, they seem squatter and are far less curved near the base. 

I believe these to be Lambeophyllum profundum. 

Fantastic. 

If Don @FossilDAWGis correct about the identity of the colonial coral that Herb sent me, and I believe he probably is, then in my hunt for an Ordovician tabulate coral, I now have acquired three of the oldest known species of rugose coral! Most splendid. Thanks to all. 

And this is just so beautiful..............

 

 

 

[ynot]

Nice pieces Adam.

[Wrangellian]

Nice! I like 'oldest' and 'youngest' fossils.

According to my chart, 454mya is upper Sandbian (of Upper Ordovician)... correct? Do you know what North American stage these are considered to be?

[minnbuckeye]

5 hours ago, Wrangellian said:

Nice! I like 'oldest' and 'youngest' fossils.

According to my chart, 454mya is upper Sandbian (of Upper Ordovician)... correct? Do you know what North American stage these are considered to be?

 

 Hope this helps:

The Millbrig K-bentonite (an altered volcanic ash bed) has been correlated with the Kinnekulle K-bentonite in Baltoscandia and throughout eastern North America. Recent efforts seem to be unraveling the complex northeast (New York & Ontario). The Millbrig, now thought to represent several volcanic eruptions over a very short time period occurs within the lower Decorah formation and allows a fixed time reference of 454 million years. 

 

 Here is a picture I found of the Decorah shale that Adam's rugosa coral came from:

[caldigger]

Now THAT is what I call a sheer cliff face!

[Tidgy's Dad]

6 hours ago, Wrangellian said:

Nice! I like 'oldest' and 'youngest' fossils.

According to my chart, 454mya is upper Sandbian (of Upper Ordovician)... correct? Do you know what North American stage these are considered to be?

Kirkfeldian Stage, I think. 

[Tidgy's Dad]

33 minutes ago, minnbuckeye said:

 

 Hope this helps:

The Millbrig K-bentonite (an altered volcanic ash bed) has been correlated with the Kinnekulle K-bentonite in Baltoscandia and throughout eastern North America. Recent efforts seem to be unraveling the complex northeast (New York & Ontario). The Millbrig, now thought to represent several volcanic eruptions over a very short time period occurs within the lower Decorah formation and allows a fixed time reference of 454 million years. 

 

 Here is a picture I found of the Decorah shale that Adam's rugosa coral came from:

Thanks, Mike, very interesting. 

T'riffic phot too. 

[minnbuckeye]

2 hours ago, Tidgy's Dad said:

Thanks, Mike, very interesting. 

T'riffic phot too. 

 

2 hours ago, Tidgy's Dad said:

Thanks, Mike, very interesting. 

T'riffic phot too. 

Found it on the internet. cannot take credit. Recognized the spot immediately. The shear cliff always provides new finds after rains and winter!!

[Tidgy's Dad]

Two-thirds of the way down Page 2 of this thread I said I wouldn't bet my fez on the brachiopod concerned being Rostricellula minnesotensis but I was leaning that way. Well, I'm glad I didn't bet as I rather like my fez. Because, after further research, it seems that R. minnesotensis appeared earlier than Rhynchotrema wisconsinense, at least as far back as the lower Platteville Fm. they then appear together for a while with Rostricellula being the much more common, but then Rostricellula disappears midway through the Decorah Shale and Rhynchotrema becomes important after that and through into the Cummingsville Fm. So the specimen shown on page 2 from the Cummingsville must be Rhynchotrema wisconsinense. 

This also leads me into the next batch of Ordovician fossils, a group of four different species from the Platteville Fm. Upper Middle Ordovician and sent to me, once again, by the inestimable Mike @minnbuckeye Oddly, though I have an awful lot of brachiopods, they mainly come from the Upper Ordovician and afterwards, so these Platteville specimens, at 454 to 455 mya are the oldest ones I have except for a single Cambrian Lingulella. 

Due to the species I have, i am even prepared to hazard a guess that these come from the Mifflin Member, near the base of the formation. 

So, first up is what i really think is - Rostricellula minnesotensis! (which also means I have R. minnesotensis from Iowa and Rhynchotrema wisconsinense from Minnesota! ) 

It's 1.3 cm wide and 1 cm tall, 0.7 cm deep. 

And then, of course, i decided to attack the poor thing with pins :

Not perfect, I know, (nor the photos) some of that matrix is quite tricky.

Tony, @Peat Burns, I will be posting a lot of brachiopods in this thread over the next several weeks, so any confirmations, alternative identifications or general help and info would be gratefully received! Thanks! 

And anyone else's input too, of course. 

 

 

 

[minnbuckeye]

@Tidgy's Dad, I clean out many of these with a drywall screw and a light hammering. If you wreck it, I just broke up some material that has many of these in it. Can resend these if needed. So whack away !

 

Mike

[Tidgy's Dad]

3 minutes ago, minnbuckeye said:

@Tidgy's Dad, I clean out many of these with a drywall screw and a light hammering. If you wreck it, I just broke up some material that has many of these in it. Can resend these if needed. So whack away !

 

Mike

Thanks, Mike, but I'm really rather fond of it now, so i'll leave it as it is. I have plenty of other things to bosh after all!  

[Wrangellian]

On 11/10/2018 at 5:58 AM, minnbuckeye said:

 

 Hope this helps:

The Millbrig K-bentonite (an altered volcanic ash bed) has been correlated with the Kinnekulle K-bentonite in Baltoscandia and throughout eastern North America. Recent efforts seem to be unraveling the complex northeast (New York & Ontario). The Millbrig, now thought to represent several volcanic eruptions over a very short time period occurs within the lower Decorah formation and allows a fixed time reference of 454 million years.

OK, then it would have to be Sandbian, based on that number against the current Timescale.

On 11/10/2018 at 6:31 AM, Tidgy's Dad said:

Kirkfieldian Stage, I think. 

That seems to correlate by the number also.. is that what you did, or did you have some other info?

[Tidgy's Dad]

2 minutes ago, Wrangellian said:

OK, then it would have to be Sandbian, based on that number against the current Timescale.

That seems to correlate by the number also.. is that what you did, or did you have some other info?

I have hand-written charts that correlate British to American formations and ages that I have assembled from various sources over the past year. 

It's quite fun and a bit frustrating as they keep moving the goalposts, so to speak.  

[Wrangellian]

4 minutes ago, Tidgy's Dad said:

I have hand-written charts that correlate British to American formations and ages that I have assembled from various sources over the past year. 

It's quite fun and a bit frustrating as they keep moving the goalposts, so to speak.  

Tell me about it... I've been trying to do this since Elementary School and my latest endeavor is here:

but it keeps changing! It would be too much work to include the British/European or other scales, but that would be useful to see.

[Tidgy's Dad]

10 minutes ago, Wrangellian said:

Tell me about it... I've been trying to do this since Elementary School and my latest endeavor is here:

but it keeps changing! It would be too much work to include the British/European or other scales, but that would be useful to see.

Very useful, it would seem. 

i'll have a good read later, but have to teach in ten minutes.

Yes, I'll have to assemble mine into a presentable form, it's all just scribbles on bits of paper just now and mainly of the Formations that i have fossils from in my collection and the overlying and underlying ones, though the Upper Middle and Upper Ordovician is fairly complete.