Calamites or Cordaites?

[historianmichael]

Many years ago my dad and I visited St. Clair, PA to collect its famed Late Pennsylvanian plant material. With the closure of St. Clair to public collecting, several years ago, we went to the next best place: Centralia, PA. In going back through our finds to ascribe a proper classification to them, I have come across several finds that I believe could either be Calamites stems or Cordaites leaves. The issue is that these fossils preserved without much detail to go on. In doing some research online and on here, I think I have figured it out, but I am not completely sure. Any help is greatly appreciated. Thanks!

 

At St. Clair, we found several of these wide impressions. It appears to lack any diagnostic features to make it easily identifiable. Calamites stems? 

  

  

At Centralia, we found this not-as-wide impression. This one does have some detail to it. You can see what looks to be veins running vertically. Cordaites leaf piece?

 

This issue though is that we also found this larger impression at Centralia that I also believe to be a Cordaites leaf. This similarly has vertical lines, but they are somewhat different from the other piece. I don't think this is a Calamites stem impression because of its width and the fact it is missing recognizable horizontal breaks. But perhaps I have this all mixed up. 

 

 

[Tidgy's Dad]

I do think the St. Clair material is very pretty.  

[Rockwood]

I believe these are all strips of lycopsid cortex that was either shed during the maturation of large trunks, or disintegrated during deposition.

[Rockwood]

There is a small piece of calamites branch in the upper right of the upper left photo however.