| details |
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 |
Middle Ordovician |
Early Gothlandian |
USSR(Russian Platform) |
Umnova,N.I. Ordovician and Silurian acritarchs of the Moscow Basin and Prebaltic |
1975 |
| details |
Cambrian |
Ordovician |
USSR(Buryat ASSR) |
Butov,Y.P. Some problems of Pre-Mesozoic stratigraphy of Savan-Baikal Mountain Region. 2. New data on the age of Pre-Mesozoic deposits. |
1986 |
| details |
Ordovician |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |