Genus Form-b
- Species total:
- 5
- Age range:
- 1600 - 17.5 MA (obsolete dating)
- IRMNG:
- find
| Name | From | To | Age range |
|---|---|---|---|
| Form-b sp | Late Proterozoic | Ottnangian |
|
| Form-b sp.1 | Late Cretaceous | Late Cretaceous |
|
| Form-b sp.2 | Cenomanian | Coniacian |
|
| Form-b sp.3 | Late Cretaceous | Late Cretaceous |
|
| Form-b sp.4 | Cenomanian | Coniacian |
|