| original |
Early Ordovician |
Late Ordovician |
Finland |
Tynni,R. On Paleozoic microfossils in clastic dykes on the …land Islands and in the core samples of Lumparn. (In: Paleozoic sediments in the Rapakivi area of the …land Islands. L. Bergman, R. Tynni and B. Winterhalter, editors.) |
1982 |
| details |
Ordovician |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |
| details |
Late Llanvirnian |
|
USSR(Estonian SSR) |
Uutela,A. et al. Ordovician acritarchs from the Rapla borehole, Estonia |
1991 |