Synedra robusta, fossil material from various Cal[ifornia?] deposits. Prepared by Wallace Frederick Reeve (no name on slide). Material looks to have been provide by Samuel Meakin. Images show parts of the full diatom to emphasize the dislocations in the structure. Olympus BHB microscope using 365nm LED light. 100x Leitz Pl Apo NA 1.32-0.60, iris closed down to give dark ground, oil immersion. Reichert Neo 1.42/1.18 condenser, oil immersion. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. Stacks done in Zerene (Dmap). Analysis in ImageJ shows a spacing of approximately 450nm between the puncta.