| original |
Late Arenigian |
Early Llanvirnian |
Germany |
Burmann,G. Diacrodia of the Lower Ordovician |
1968 |
| details |
Early Ordovician |
|
Nd |
Downie,C. Observations on the nature of the acritarchs |
1973 |
| details |
Tremadocian |
Arenigian |
Wales |
Downie,C. et al. Changes in the acritarch assemblages at the Tremadoc boundaries in the United Kingdom. |
1979 |
| details |
Nd |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |
| details |
Ordovician |
|
Nd |
Servais,T. An annotated bibliographical review of Ordovician acritarchs |
1997 |