Strew slide from Silver Lake, Pembroke, Ontario. Fossil freshwater. Variety of species. Mounted in Aroclor and dated June 1975. Prepared by Bernard Hartley. Olympus BHB microscope using 450nm LED light. I chose an example of a Pinnularia sp. for high magnification imaging. 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. 32 images stacked in Zerene (Pmax).
I think this is probably Pinnularia pulchella var. Canadensis (from the Diatoms of North America website – https://diatoms.org/species/224484/pinnularia-pulchella-var-canadensis).
Silver Lake is mentioned a couple of times in Bernard Hartley’s Sample and Strew Slide Collection PDF (accessed from here). However this slide does not have an ID number so I can’t pin it down to a specific entry.