The goal of this study was to investigate type materials of 22 Navicula species described by Ruth Patrick in 1959. Type specimens of two species could not be found on the holotype slides. The holotypes of 20 other taxa were located and imaged. Specimens of 11 taxa from type materials or from the type localities were investigated with electron microscopy and the details of their ultrastructure were described. On the basis of this examination, six Navicula species were transferred to other genera. The following new combinations were made: Hippodonta dulcis Potapova nom. nov., H. gravistriata (Patrick) Potapova comb, nov., Fallacia latelolongitudinalis (Patrick) Potapova comb, nov., F. duomedia (Patrick) Potapova comb, nov., Selllaphora subfasciata Potapova nom. nov., and S. secura (Patrick) Potapova comb. nov. Based on the available data, nine species described by Patrick were found to be taxonomic synonyms of taxa described earlier by other authors. Future studies of more abundant populations of Patrick's species and type materials of the taxa assumed to be synonymous, may, however, reveal differences between them and prove some of Patrick's taxa to be separate species.