Plate 1. Scale bar = 10 µm unless otherwise indicated. All are scanning electron microscope (SEM) pictures from Sample 162-983A-13H-7, 49-50 cm. 1, 2. Thalassiosira oestrupii (Ostenfeld) Proshkina-Lavrenko, external views of valve face with a central process and a labiate process halfway between the center and the margin. 3. Thalassiosira oestrupii (Ostenfeld) Proshkina-Lavrenko, internal view of valve face with a row of marginal spines, with a central process and a labiate process halfway between the center and the margin. 4. Proboscia curvirostris Jordan and Priddle. 5. Neodenticula seminae (Simonsen and Kanaya) Akiba and Yanagisawa, internal view of valve face. 6. Neodenticula seminae (Simonsen and Kanaya) Akiba and Yanagisawa, internal view of valve face. Scale bar = 1 µm. 7. Nitzschia reinholdii Kanaya and Koizumi, at lower left, and Nitzschia fossilis (Frenguelli) Kanaya, at top right. 8. Nitzschia fossilis (Frenguelli) Kanaya, internal view. 9. Nitzschia fossilis (Frenguelli) Kanaya, external view.