| details |
Late Arenigian |
Early Llandeilian |
USSR(Estonian SSR) |
Uutela,A. et al. Ordovician acritarchs from the Rapla borehole, Estonia |
1991 |
| original |
Late Llanvirnian |
|
USSR(Estonian SSR) |
Uutela,A. et al. Ordovician acritarchs from the Rapla borehole, Estonia |
1991 |
| details |
Early Ordovician |
Middle Ordovician |
USSR(Estonian SSR) |
Sarjeant,W.A.S. et al. The Micrhystridium and Veryhachium Complexes (Acritarcha: Acanthomorphitae and Polygonomorphitae): A taxonomic reconsideration. |
1994 |
| details |
Late Arenigian |
Early Llanvirnian |
Sweden |
Ribecai,C. et al. Arenigian acritarch from Horns Udde (Oland, Sweden). A preliminary report. |
1995 |