Rare Petrified Calamites (Arborscent Horsetail). Coal Basin of Eastern Donbass. Please check out my other listings for rare Petrified Woods. The item “Rare Petrified Wood Calamites Horsetail E. Donbass, Russia Carboniferous 8.25×5″ is in sale since Friday, January 29, 2021. This item is in the category “Collectibles\Rocks, Fossils & Minerals\Fossils\Vegetation\Petrified Wood”. The seller is “howard_and_sons” […]