Pennsylvanian Flora from East Central Illinois

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This is my nicest and largest Lepidodendron branch, and another example of a piece with a part and counterpart. I like the nicely contrasting black and red of the shale too.

 

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And here are two more, quite different, examples of Lepidodendron. The first is very small, and shows a strong keel on each scale. 

 

 

The next is larger specimen that shows the more typical diamond-shaped pattern with leaf scars. 

 

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These are a few of my better partial leaves. First, an Alethopteris with some good depth. 

 

 

Next, a well-preserved but incomplete Cordaites. 

 

 

And finally, another Pecopteris-like pinna with a few partial pinnules. 

 

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This morning's post is one of my more unusual finds from this site, in terms of preservation especially. Unlike the usually flat or slightly dimensional finds, this piece is fully 3-dimensional, wrapping around a large block. It appears to be Syringodendron, the underbark of the Sigillaria tree, but it seems like the individual "cords" that make up the bark have separated? This has resulted in these individual structures being preserved, with the typical evenly-spaced scars. 

 

 

Then on the opposite side of the piece is another one. 

 

 

And finally, visible on the top side of the piece as pictured above are a set of what I think are the same structures, except now preserved flat instead of inflated like the others. 

 

 

I can't say I have seen any documentation of this sort of "separated Syringodendron" before, although maybe since it represents a partially decomposed and degraded example it is not something that would be recorded. 

 

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Today I would like to share 2 examples of an extremely common Pennsylvanian plant form genus, Stigmaria. This form represents the root structures of lycopsid trees like Lepidodendron and Sigillaria. 

 

The first is a more typical preservation, which I have found multiple examples of. It is preserved with some dimensionality and another fascinating trait present in some fossils from this site- it actually shows both sides of the material being preserved. The structure is definitely distorted by the fossilization process, but it gives an interesting insight into the anatomy of the specimen- you can the scars where the "rootlets" attached run all the way through. 

 

 

 

The other example I have shows a radically different preservation. This one is more akin to the Asolanus I posted earlier, preserved nearly flat with intricate details preserved. The picture does not capture the level of subtle texture that is present. 

 

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This evening I want to share another multi-layered fossil- this one seems to show a few different types of sub-surface bark from a lycopsid tree, and then on the reverse, some non-descript wood from the inside of the tree. The form genera for the inner bark with the slit-like scars is Aspidiopsis. 

 

 

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Having spent some more time looking at references as I post these, I think the two part red and black branch above should actually be Lepidophloios instead. Here is another example of that genus, with larger and coarser scales. 

 

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This morning I have a mix of flora to share. First is another example of bark, in this case another species of Sigillaria. 

 

 

Next is a nice little fern, something like Pecopteris or Lopatopteris? 

 

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Here is another type of common Carboniferous plant that is rare at this site- Calamites. This is my best example by far and it's not a particularly good one. The rarity of this genus aligns well with the infrequency of other horsetail components here, such as Annularia and Asterophyllites.

 

 

[bigred97]

I love bark - you are so lucky to have this site with a gret variety of species and specimens. Your comment about the Calamites got me to thinking. I understand that the Mazon Creek concretions are accepted as originating from a coastal river delta sort of environment that was located near the equator at the time. I wonder if the types and frequency of species you are finding gives any indication of their original locale? It seems like it may have been different than that of Mazon Creek. Perhaps it was more inland?

 

I can't wait to see what else you find! Chris

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On 5/24/2020 at 1:25 PM, bigred97 said:

I love bark - you are so lucky to have this site with a gret variety of species and specimens. Your comment about the Calamites got me to thinking. I understand that the Mazon Creek concretions are accepted as originating from a coastal river delta sort of environment that was located near the equator at the time. I wonder if the types and frequency of species you are finding gives any indication of their original locale? It seems like it may have been different than that of Mazon Creek. Perhaps it was more inland?

 

I can't wait to see what else you find! Chris

Thanks! Yes, I will definitely have to do some more reading of the literature on variation in Pennsylvanian flora and what they may mean for the environment-I know there are many papers and books out there on it. 

 

On topic of horsetails, I have shown my only example of an Annularia and my best Calamites. Here is the only Asterophyllites I have found yet- a faint impression of some tiny leaves and nothing more. Each whorl is only about 5 MM high. 

 

 

When I first saw it in the field I wasn't even sure what it was. It was on the reverse of this piece, a fairly typical hash plate with a mix of incomplete leaves- Pecopteris, Cordaites, and Cyperites. 

 

Edited May 26, 2020 by deutscheben
Fixed typo

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I'll finish off the evening with a few more pieces of bark. First is a clear piece of Syringodendron sub-surface bark. 

 

 

The next one is more nebulous- definitely some kind of lycopod bark, but I'm not sure what it would be classified as- it doesn't have any real clear defining features. It does have an interesting yellow color, likely due to sulphur content I would guess. 

 

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Here is a smaller grey plate featuring Pecopteris? and Cyperites leaves.

 

 

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Today I would like to share one of my nicer hash plates. This one has very crisp detail, nice colors, and some more complete leaves/pinnules on it. It is mostly Alethopteris, but it does also have one Neuropteris leaf too. 

 

 

 

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For today, I want to share another Alethopteris, this one a negative impression of a pinnule.

 

 

And this interesting bark impression of some kind. I would guess it represents a lower level of bark from a lycopod. 

 

[Peat Burns]

Wow.  Beautiful preservation and diversity. 

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21 hours ago, Peat Burns said:

Wow.  Beautiful preservation and diversity. 

Thanks so much! 

 

The 2 most commonly encountered barks from these sites are from a kind of Lepidodendron, I think. One features long and uneven stretched-out diamond-shapes, with no visible leaf scars. Here is an example:

 

 

I'm not sure what the prominent ridge running down the middle is. 

 

The other bark appears to be from the same kind of tree, based on examples I've found in direct association. From the arrangement of the bark in those pieces, and from what I've seen in the literature, I think the bark above is the outer layer, while this second one is the layer directly below.

 

This example showing both barks is another one of my favorites:

 

 

The underbark layer can be seen on the left side. 

 

And here is an example just showing the underbark layer:

 

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It is a little strange though, because the second type of bark more closely resembles the inner bark Syringodendron with its furrowed rows, which is supposed to be associated with Sigillaria, not Lepidodendron.  I'm actually not sure exactly what the diamond-ridged bark is- I have seen some diagrams that indicate the older, lower bark on the tree would elongate and lose the leaf scars, so maybe that explains it?

 

On the other hand, I found this tiny example (about 1 inch square) of bark that seems to show a similar pattern to the ones above. 

 

 

So, lots of mysteries with these. I will share a few more examples of similar types in later posts. I would love to hear if anyone with more expertise in Pennsylvanian flora has more thoughts. 

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This is my largest fossil from this site- actually, I think the largest fossil in my collection overall. It is another example of an "underbark" type like those I posted above.

 

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Here is another large piece demonstrating a relationship between the two bark types above, albeit one that is a little confusing. This big hunk actually featured multiple impressions on a few sides. Here is the largest impression, what I will call the top. 

 

 

On the opposite side from this is a smaller impression of similar bark. 

 

 

Finally, a third much smaller section of bark was on the back side, but I separated it when breaking down the block for transport. 

 

 

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As I said, the corresponding Syringodendron -like bark was also preserved on this piece. Unlike the yellowish sample above where it appears to be below the ridged surface bark, though, on this one the two barks are preserved facing each other. 

 

On the top side I was able to break off a small piece to show this. 

 

 

 

A similar situation was also present with the bottom impression of the Lepidodendron- like bark

 (2nd pic in the post above). This impression was facing that ridged bark. 

 

 

I'm not quite sure how to interpret these impressions. Was it multiple layer of bark from trees that were preserved laying on top of each as they fell in the water? Or was the underbark layer from the same tree somehow flipped around as it decayed? It certainly does not seem to depict the living orientation of the bark based on what I have read about these trees. 

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For today I have another mix of different things. First, a small fern tip. I'm really not confident about an ID on this one, but it's very cute and dainty. 

 

 

And next is some more bark. This one seems slightly different than the previous ones I have posted- the ridges almost look braided? But it may just be a different part of the tree or different growth stage. 

 

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After a little pause, I am back with more. First is another example of a multilayered bark piece. I'm not sure if the top and bottom layers come from the same plant, or two different ones, and I'm not confident in an ID for either. 

 

 

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My second post for today is another double-sided one, but with ferns. The first one is a Pecopteris-type, it's pretty beat up, missing many pinnae. 

 

 

The other fern is, I think, another Crenulopteris. (with another more incomplete one present too)

 

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It’s been quite a hiatus for this thread, I’m afraid not being able to fossil hunt much in the last year has made it hard to stay motivated. But I was reminded of it recently and remembered that I had not shared pictures of my finds from a second spoil pile in the area. 
 

This second pile was largely reclaimed about 20 years ago, but a small portion of it still exposes the waste tailings from the mine- I believe the fossils also come from the Pennsylvanian Energy Shale member of the Carbondale Formation. 
 

Here I have found concretionary fossils, more akin to those found at Mazon Creek. I have almost exclusively discovered plant material in them, along with one Palaeoxyris shark egg casing. 
 

It is Palaeoxyris prendelli, a species I have also found at sites just to the west and over the border in Indiana. A scientific paper on finds in the area indicated that fossils from some nearby sites were dominated by this genus, in some cases it made up 75% of the finds. Was this area a Carboniferous shark nursery?