Umbonium sp.
| 1923. | Umbonium sp. |
| Condition: | Present |
| Taxonomy: | Mollusca: Gastropoda: Trochidae: |
| Geologic Time: | Cenozoic: |
| Yokoyama, M., 1923d: Tertiary fossils from Kii. Japanese Journal of Geology and Geography, vol. 2, no. 3, pp. 47–58, pls. 6–7. (Reference No. 0470) |
| Ichikawa, T., 1983, no. 9, p. 295. |
