| original |
Late Caradocian |
Early Ashgillian |
Canada(Anticosti Island) |
Achab,A. Chitinozoa from the Dicellograptus complanatus zone, Vaureal Formation (Upper Ordovician) Ile d'Anticosti, Quebec. |
1977 |
| details |
Ashgillian |
|
Canada(Anticosti Island) |
Achab,A. Chitinozoa from the Climacograptus prominens elongatus zone, Vaureal Formation (Upper Ordovician) Ile d'Anticosti,Quebec. |
1977 |
| details |
Middle Ashgillian |
Late Ashgillian |
North America |
Jenkins,W.A.M. et al. Stratigraphic ranges of selected chitinozoa. |
1979 |