A strew slide from Sharktooth Hill, California. Nice range of species. Prepared by Klaus Kemp. Mounted in Pleurax and dated January 2003. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. Image stacks prepared in Zerene (Pmax).
Cymatogonia amblyoceras. Viewed from the underside. Fairly sure on this one. Have also seen it named Triceratium amblyoceras and Actinoptychus amblyoceras.
Actinoptychus perisetosus ? The name for this came from Hanna, G.D. (1932). The diatoms of Sharktooth Hill, Kern County, California. Proceedings of the California Academy of Sciences 20(6): 161-263, plates 2-18. Not been able to find more high resolution images to compare it with so am leaving this with a question mark for now.