Biostratigraphic zonation and eocene chlorophytal algae, assiut-minia stretch, nile valley, egypt

The Early and Middle Eocene rocks at Assiut-Minia stretch are shallow marine limestones. These rocks consist of three rock units namely, Drunka, Minia and Samalut formations. Four algal and larger foraminiferal zones are recorded from these rocks namely in stratigraphic order Ovulites pyriformis/Ovulites arabica, Nummulites planulatus, Alveolina oblonga/Orbitolites complanatus and Nummulites gizehensis zones. Also, these rocks are characterized by high-diversified green algal floras (both Bryopsidales and Dasycladales). Nine Dasycladales taxa are identified (six of species-level and three of genus-level). They are Belzungia silvestrii (Pfender) Massieux, Cymopolia elongata (Defrance), Furcoporella diplopora Pia, Niloporella subglobosa Dragastan & Soliman, Clypeina cf. rotella Yu-Jing, Acicularia robusta Dragastan & Soliman, Dissocladella sp., Cymopolia sp. and Neomeris sp. A total of nine Bryopsidales (seven of species-level and two of genus-level) are recorded. They are represented by Ovulites pyriformis Schwager, Ovulites arabica (Pfender), Ovulites morelleti Elliott, Ovulites marginulata (Lamarck), Ovulites elongata Lamarck, Halimeda nana Pia, Halimeda praemonilis Morellet, Halimeda sp. and Ovulites sp. The paleoecological importance of the described algae is also discussed and