What species of Calamite is this

[paleo.nath]

I know these two are Calamites but I’m unsure how to identify the species.

They were both found in the North Attleboro part of the Rhode Island formation and I’m thinking the larger one is C. Cistii? 

 

[Rockwood]

There is a chance evidence in the first photo represents enough of the external morphology to be identified at the species level. The second, being a pith cast, I hold out less hope on.

[Fossildude19]

These are the species found in the Rhode Island Formation/Narragansett Basin. 

 

 

You might have to go with 10.

C. carinatus and C. cistii are more commonly found there.

However you can do a bit more research HERE. 

 

Visual Aids.