A strew slide from Kreyenhagen shale (California, USA). Fossil Eocene. Range of species, with quite a high proportion of Xanthiopyxis species. Prepared by Emiliano Bellotti. Mounted in Pleurax and dated 2024.
I managed to find thee two next to each other. Actinoptychus sp. (A. undulatus maybe) and Xanthiopyxis sp. (seems to be Xanthiopyxis acrolopha). It is an inside view of half of a Xanthiopyxis. 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. 60 images stacked in Zerene (Pmax).
Some background information on this location; Hanna, G. Dallas. “The Lowest Known Tertiary Diatoms in California.” Journal of Paleontology, vol. 1, no. 2, 1927, pp. 103–27. JSTOR, http://www.jstor.org/stable/1297922.