| details |
Cambrian |
Ordovician |
USSR(Russian Platform) |
Umnova,N.I. et al. Acritarchs from the Yaroslavskoi series of the northern part of the Russian Platform |
1970 |
| original |
Middle Ordovician |
|
USSR(Yaroslav) |
Umnova,N.I. et al. Acritarchs from the Yaroslavskoi series of the northern part of the Russian Platform |
1970 |
| details |
Cambrian |
Tremadocian |
USSR(Russian Platform) |
Umnova,N.I. et al. Acritarch assemblages from the Cambrian and Early Ordovician sediments of western and northwestern Russian Platform. (In: Palynology research in Byelorussia and other Regions of the USSR) |
1971 |
| details |
Tremadocian |
|
USSR(Moscow) |
Ivanova,T.D. Cambrian-Ordovician boundary Beds of the Moscow Syneclise |
1975 |
| details |
Ordovician |
Silurian |
USSR(Russian Platform) |
Umnova,N.I. Ordovician and Silurian acritarchs of the Moscow Basin and Prebaltic |
1975 |
| details |
Middle Ordovician |
|
USSR(Yaroslav) |
Umnova,N.I. Ordovician and Silurian acritarchs of the Moscow Basin and Prebaltic |
1975 |