1. Species Geisonoceras teicherti Flower, 1939 †
2. Species Geisonoceras wegelini (Angelin, 1880) †
3. Species Geisonoceras amplicameratum (J. Hall, 1847) † accepted as Ordogeisonoceras amplicameratum (J. Hall, 1847) † (unaccepted > superseded combination)
4. Species Geisonoceras foerstei Strand, 1934 † accepted as Ordogeisonoceras foerstei (Strand, 1934) † (unaccepted > superseded combination)
5. Species Geisonoceras heroyense Strand, 1934 † accepted as Isorthoceras heroyense (Strand, 1934) † (unaccepted > superseded combination)
6. Species Geisonoceras junceum (J. Hall, 1847) † accepted as Isorthoceras junceum (J. Hall, 1847) † (unaccepted > superseded combination)
7. Species Geisonoceras lineolatus (J. Hall, 1847) † accepted as Isorthoceras lineolatum (J. Hall, 1847) † (unaccepted > superseded combination)
8. Species Geisonoceras strangulatum (J. Hall, 1847) † accepted as Isorthoceras strangulatum (J. Hall, 1847) † (unaccepted > superseded combination)
9. Species Geisonoceras strigatum (J. Hall, 1847) † accepted as Isorthoceras strigatum (J. Hall, 1847) † (unaccepted > superseded combination)
10. Species Geisonoceras tenuistriatum (J. Hall, 1847) † accepted as Isorthoceras tenuistriatum (J. Hall, 1847) † (unaccepted > superseded combination)
11. Species Geisonoceras tenuitextum (J. Hall, 1847) † accepted as Isorthoceras tenuitextum (J. Hall, 1847) † (unaccepted > superseded combination)

The webpage text is licensed under a Creative Commons Attribution 4.0 License