| details |
Middle Ordovician |
|
Sweden |
Sarjeant,W.A.S. et al. The Micrhystridium and Veryhachium Complexes (Acritarcha: Acanthomorphitae and Polygonomorphitae): A taxonomic reconsideration. |
1994 |
| details |
Ordovician |
|
Estonia |
Uutela,A. Extent of the Northern Baltic Sea during the Early Palaeozoic Era: New Evidence from Ostrobothnia, western Finland. |
1998 |
| details |
Ordovician |
|
Finland |
Uutela,A. Extent of the Northern Baltic Sea during the Early Palaeozoic Era: New Evidence from Ostrobothnia, western Finland. |
1998 |