| original |
Early Ashgillian |
Middle Ashgillian |
Canada(Anticosti Island) |
Jacobson,S.R. et al. Acritarch biostratigraphy of the Dicellograptus complanatus graptolite zone from the Vaureal form Ation, (Ashgillian), Anticosti Island, Quebec, Canada. |
1985 |
| details |
Late Ordovician |
|
Canada(Quebec) |
Sarjeant,W.A.S. et al. The Micrhystridium and Veryhachium Complexes (Acritarcha: Acanthomorphitae and Polygonomorphitae): A taxonomic reconsideration. |
1994 |
| details |
Ashgillian |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |