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Pennsylvanian Plant Fossil Confusion


Lucid_Bot

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Lucid_Bot

Hi. The geological info for this find is: Pennsylvanian (Carboniferous), Conemaugh Group, Glenshaw Formation. I've been digging at an outcrop near a local stream and finding a lot of pecopteroids, neuropteroids, calamites, some sphenopteroids and possibly lepidodendron/stigmaria, sigillaria and cordaites. Recently the rain washed away the dirt at the base of this outcrop. Cutting away the rock at the base I found at least a dozen instances of these somewhat cylindrical and flat-topped and flat-bottomed rocks sitting one on top of the other. The first picture shows a cavity from which I removed some of these rocks. I don't know if it helps, but there's a lot of iron in this area. Any ideas would be appreciated.

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0908211459_HDR.jpg

0908211500a_HDR.jpg

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Fossildude19

Welcome to the Forum. :)

Could they be infilled burrows, or root casts?

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Lucid_Bot

Thanks. I really don't know what an infilled burrow is. Although I was thinking root casts when I saw them. Should've mentioned this, but all over the base was a pattern that sort of reminded me of stigmaria (a little like a honey comb), but also vertical groves like calamites. Certainly anyone's guess is better than mine here. They couldn't be bones could they?

Edited by Lucid_Bot
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Due to the lack of a 'pith-cast', I do not think these are Stigmaria. If you see a 'diamond pattern', they could be Lepidodendron.

 

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Lucid_Bot
8 minutes ago, Auspex said:

Due to the lack of a 'pith-cast', I do not think these are Stigmaria. If you see a 'diamond pattern', they could be Lepidodendron.

 

 

If you don't mind me asking: why would such branches be separated into discreet units and not just one long piece? Thanks btw.

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Fossildude19
3 minutes ago, Lucid_Bot said:

 

If you don't mind me asking: why would such branches be separated into discreet units and not just one long piece? Thanks btw.

 

Decomposition and/or breakage from storm damage.

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Fossildude19
34 minutes ago, Lucid_Bot said:

Thanks. I really don't know what an infilled burrow is. They couldn't be bones could they?

 

 

Infilled burrows would be burrows made by crustaceans or other invertebrates, that become filled with mud, then turn to stone.

A cast of a burrow, if you will.

 

There is no way these are bones - no bone texture or morphology.

 

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Lucid_Bot
3 minutes ago, Fossildude19 said:

 

 

Infilled burrows would be burrows made by crustaceans or other invertebrates, that become filled with mud, then turn to stone.

A cast of a burrow, if you will.

 

There is no way these are bones - no bone texture or morphology.

 

 

I've been doing this by myself since I started. Very nice to just get answers from someone, so thanks again!

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Fossildude19

Happy to help out.

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That's a calamites forcing it's way up through overburden like a horsetail through blacktop.

I think. :unsure:

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Fossildude19
30 minutes ago, Rockwood said:

That's a calamites forcing it's way up through overburden like a horsetail through blacktop.

I think. :unsure:

 

I don't see enough structure in them to say it's Calamites. :unsure: 

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22 minutes ago, Fossildude19 said:

 

I don't see enough structure in them to say it's Calamites. :unsure: 

Step back and look at the fuzzy picture, then note the folding in the very plant like surface texture in the cleanly separated sections.

If that ain't structure .. . .

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1 hour ago, Rockwood said:

That's a calamites forcing it's way up through overburden like a horsetail through blacktop.

I think. :unsure:

I know what you're saying, but I can't rule it in, or out. The things are bordering on nondescript.

@Lucid_Bot

Sometimes wetting things of this nature will bring out hidden details.

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Lucid_Bot

I think you can see the pattern better on this. It has ridges running vertically and bumps. I

thumbnail.jpeg

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Humm . . . Rows of circles lined up in columns = sigillaria.

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Lucid_Bot
6 hours ago, Rockwood said:

Humm . . . Rows of circles lined up in columns = sigillaria.

 

I don't know if this helps, but on closer examination it seems to have this pattern:

0909210940b~2.jpg

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Petalodus12
19 hours ago, Lucid_Bot said:

Hi. The geological info for this find is: Pennsylvanian (Carboniferous), Conemaugh Group, Glenshaw Formation. I've been digging at an outcrop near a local stream and finding a lot of pecopteroids, neuropteroids, calamites, some sphenopteroids and possibly lepidodendron/stigmaria, sigillaria and cordaites. Recently the rain washed away the dirt at the base of this outcrop. Cutting away the rock at the base I found at least a dozen instances of these somewhat cylindrical and flat-topped and flat-bottomed rocks sitting one on top of the other. The first picture shows a cavity from which I removed some of these rocks. I don't know if it helps, but there's a lot of iron in this area. Any ideas would be appreciated.

0907211503b.jpg

0908211458_HDR.jpg

0908211459_HDR.jpg

0908211500a_HDR.jpg

These are root casts. I know this outcrop, and these are extremely abundant there. The ones that I have found do not retain enough of the plant material to make a confident ID. Stratigraphically, this zone is located in the Mason Shales, below the Brush Creek Limestone. I can PM you with more information about this outcrop, including a complete floral list if you would be interested. 

 

I would also suggest that you are extremely careful when digging here. For one, this outcrop is quite unstable. Also, the surrounding environment retains one of the most biodiverse plant ecosystems in Allegheny County, so attempting not to damage this ecosystem should be a top priority. I hike there often, so I hope to see you there!

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Lucid_Bot
29 minutes ago, Petalodus12 said:

These are root casts. I know this outcrop, and these are extremely abundant there. The ones that I have found do not retain enough of the plant material to make a confident ID. Stratigraphically, this zone is located in the Mason Shales, below the Brush Creek Limestone. I can PM you with more information about this outcrop, including a complete floral list if you would be interested. 

 

I would also suggest that you are extremely careful when digging here. For one, this outcrop is quite unstable. Also, the surrounding environment retains one of the most biodiverse plant ecosystems in Allegheny County, so attempting not to damage this ecosystem should be a top priority. I hike there often, so I hope to see you there!

 

That outcrop has yielded some great finds for me. I'm very interested in whatever information you can provide. And thanks for the warning, I've noticed its instability. Hopefully see you around and thanks for the response.

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