1–10 Fragilaria vaucheriae? [F. perminuta?] (6957) 11, 12 Fragilaria sp. (6956) 13–18 Fragilaria sp. (6957) 19, 20 Fragilaria tenera (6956) 21 Fragilaria sepes (6955) 22–26 Fragilaria amphicephala (6957) 27 Ulnaria ulna? (6958) 28–31 Hannaea arcus (6956). Scale bar: 10 µm.