| details |
Oeland |
Early Virgulian |
Estonia |
Nolvak,J. Biostratigraphy: Ordovician chitinozoans |
1990 |
| details |
Early Kunda |
|
Estonia |
Magi,S. Locality 4:2 Cntika Clint |
1990 |
| details |
Late Arenigian |
Early Llanvirnian |
Baltic |
Nolvak,J. et al. Ordovician chitinozoan zones from Baltoscandia |
1993 |
| details |
Late Arenigian |
Early Llanvirnian |
Scandinavia |
Nolvak,J. et al. Ordovician chitinozoan zones from Baltoscandia |
1993 |
| details |
Late Volkov |
Aseri |
Baltic |
Lindstrom,M. et al. Post-impact deposits in Tvaren, a marine Middle Ordovican Crater Southern of Stockholm, Sweden |
1994 |