| 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 |
Late Cambrian |
|
USSR(Estonian SSR) |
Kheinsalu,K. et al. Cambrian-Ordovician boundary beds in the Saka Ii section, Northern East Estonia. |
1990 |
| details |
Early Ordovician |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |
| details |
Late Cambrian |
Early Ordovician |
Algeria |
Stricanne,L. et al. A statistical approach to classification of the Cambro-Ordovician galeate acritarch plexus |
2002 |