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Some mystery fern fossils from St. Clair


Shamalama

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Here are a couple of "old" pieces from St. Clair that I found. The first one is a faint trace that I think is Pectopteris but I find it so rarely at St. Clair I can't tell for sure. What is throwing me off is that the leaflets are getting longer as they progress along the rachis whereas I have always thought that Pectopteris had a consistent leaflet length along the whole leaf.

 

IMG_7056.thumb.jpg.9356d3e1fdfa604806de73ed8f58b63b.jpgIMG_7055.thumb.jpg.85cb0a19537fdd04e77639d291bd55d1.jpg

 

Then the second piece is a cluster of leaves/leaflets that don't match anything I've seen before. The tips of the leaves are not pointed enough for Alethopteris and not wide enough for Neuropteris.

IMG_7059.thumb.jpg.b5e883b6479e003df269640b9e3cce6c.jpg

IMG_7058.thumb.jpg.023fd08578478c7ae16e13ac2bde2590.jpg

 

Any suggestions are appreciated.

-Dave

__________________________________________________

Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPhee

If I'm going to drive safely, I can't do geology. - John McPhee

Check out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/

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Hey Dave, great finds!

The first one reminds me of Lyginopteris

Maybe @fiddlehead or @fossilcrazy  @docdutronc @paleoflor will chime in. 

 

    Tim    VETERAN SHALE SPLITTER

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I agree that the first one is quite a find. And till now unreported as far as I know from the St Clair area. I believe the second one, which was poorly preserved and only appears more interesting than I believe it to be. Based on the lack of even a crease to show any midveins in the pinnules, leads me to believe they did not have any. The only genus which lacks a midvein is Odontopteris. And the only species of Odontopteris reported at St. Clair is O. subcuneata. I don't know that this species is that "common" there but since O. subcuneata is a polymorphic form Macroneuropteris scheuchzerii and it is a common element in this flora, so it should be readily found there. The other features that can be made out also help confirm the taxon. The first one is very rare even where it is known to exist. So much so it is only described on fertile foliage and only one example of sterile foliage is known to exist. It is called Stellatheca ornata and you have a fertile example. A brief description; The ultimate and penultimate rachis appears wide (though partially due to pinnules being slightly confluent) Each pinnule typically has three sori, but can range from two to five, and are placed near the margin. And the pinnules are generally no more than rounded lobes. Attached is a picture of a Mazon Creek example.

 

Hope this helps,

Jack

 

 

Stl.ornPP54627.jpg

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11 hours ago, fiddlehead said:

I agree that the first one is quite a find. And till now unreported as far as I know from the St Clair area. I believe the second one, which was poorly preserved and only appears more interesting than I believe it to be. Based on the lack of even a crease to show any midveins in the pinnules, leads me to believe they did not have any. The only genus which lacks a midvein is Odontopteris. And the only species of Odontopteris reported at St. Clair is O. subcuneata. I don't know that this species is that "common" there but since O. subcuneata is a polymorphic form Macroneuropteris scheuchzerii and it is a common element in this flora, so it should be readily found there. The other features that can be made out also help confirm the taxon. The first one is very rare even where it is known to exist. So much so it is only described on fertile foliage and only one example of sterile foliage is known to exist. It is called Stellatheca ornata and you have a fertile example. A brief description; The ultimate and penultimate rachis appears wide (though partially due to pinnules being slightly confluent) Each pinnule typically has three sori, but can range from two to five, and are placed near the margin. And the pinnules are generally no more than rounded lobes. Attached is a picture of a Mazon Creek example.

 

Hope this helps,

Jack

 

 

Stl.ornPP54627.jpg

 

Jack, Thanks so much for the ID assistance. I looked up pictures for Odontopteris  and it does seem like the second set of pictures matches that.  The Stellatheca ornata is a really cool find and your example looks to be right on the money. The thicker rachis with shallow pinnules really sets it apart from anything else I have found from St. Clair. Even old finds can yield something new!

-Dave

__________________________________________________

Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPhee

If I'm going to drive safely, I can't do geology. - John McPhee

Check out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/

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  • 1 month later...
On 11/19/2017 at 6:52 PM, Fossil-Hound said:

Very nice ferns. It's a shame St. Clair is now closed to the public.

is it closed to the public? why?

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On 1/15/2018 at 6:26 PM, hashemdbouk said:

is it closed to the public? why?

 

St. Clair has been closed to collecting by the land owners - Reading Anthracite, since July of 2015.

It is patrolled by private security, and people are/have been being arrested and charged with Criminal Trespass. :(

They only allow school groups to collect, and you need written permission from Reading Anthracite office to go there.

Regards,

    Tim    VETERAN SHALE SPLITTER

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__________________________________________________
"In every walk with nature one receives far more than he seeks."
John Muir ~ ~ ~ ~   ><))))( *>  About Me      

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On 1/15/2018 at 4:26 PM, hashemdbouk said:

is it closed to the public? why?

Yes it is. Talk to Reading Anthracite.

Do or do not. There is no try. - Yoda

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