Plant microfossils from the Llandoverian and Wenlockian rocks of Pennsylvania

Macerations of greenish shales from the Tuscarora Formation (Llandoverian) and Clinton? strata (Wenlockian) in central and eastern Pennsylvania yield a remarkable assemblage of spores and probable spores, dyads, spore tetrads, tubular and cuticle-like structures. These are considered as remains of a pre-vascular plant, terrestrial flora and are discussed according to this in- terpretation. Although this study is preliminary in nature, we have described the following new taxa: Rugosphaera tuscarorensis (n.gen., n.sp.), Tetrahedraletes medinensis (n.gen., n.sp.), Nodospora burnhamensis (n.gen., n.sp.), Nodospora rugosa (n.sp.), Nodospora oyleri (n.sp.), Dyadospora murusattenuata (n.gen., n.sp.) and Dyadospora murusdensa (n.sp.).