ISM 15752
Calamites sp. is the pith cast of the stem of an extinct horsetail. Scouring rushes (Equisetum spp.) are modern representatives of this group.
These horsetails (Sphenopsida) were arborescent (tree-like) and grew to a height of up to 10 meters (31 feet).
Whorls of leaves, such as Asterophyllites, would have been present on these types of plants.