Sphenophyllum sp. Fossil Plant Plate – Carboniferous (Pennsylvanian) – Llewellyn Formation, St. Clair, Pennsylvania, USA A very attractive fossil plant plate from the Carboniferous Period (Pennsylvanian), collected from the well-known Llewellyn Formation of St. Clair, Pennsylvania—one of the most classic North American localities for fossil flora. This specimen displays multiple well-preserved impressions of Sphenophyllum sp., an extinct climbing plant related to modern horsetails. The fossil clearly shows the distinctive whorled arrangement of wedge-shaped leaves radiating from slender stems, a diagnostic feature of the genus. The preservation is particularly striking: light grey to whitish plant impressions stand out sharply against the dark shale matrix, creating strong natural contrast and making the delicate structures easy to observe. Several stems with repeated leaf whorls are visible across the slab, giving a pleasing and balanced composition. Fine details of the leaf shape and organization are well defined, and the fossilization beautifully captures the original plant morphology typical of Carboniferous coal forest vegetation. The slab is naturally split, with additional partial impressions visible on the reverse side, illustrating the natural part and counterpart preservation typical of shale-hosted plant fossils. Dating to approximately 300 million years ago, Sphenophyllum was part of the dense and humid coal forest ecosystems that once dominated this region. A classic and visually appealing palaeobotanical specimen, ideal for collectors of Carboniferous plants, educational collections, or natural history display. Display stand included.