Slide labelled as 2x Chaetoceros sp., and 1x Navicula sp. (resembles Navicula pusilla = Cosmioneis pusilla). So I shall go with that name but leave a quesrion mark after it for now. Prepared by RI Firth, and I can’t read the rest of the writing. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 33 images stacked in Zerene (Pmax).