| details |
Silurian |
Early Devonian |
USSR(Permsk Oblast) |
Lagutenkova,N.S. et al. New data on Old rocks in the Yaborovskaya area in the northeastern part of the Perm Oblast |
1977 |
| details |
Vendian |
|
USSR(Permsk Oblast) |
Lagutenkova,N.S. et al. Separation of Lower Paleozoic deposits in the northeastern Perm District. (In: Voprosy biostratigrafii i Paleogeografii Neftegazonosnykh Oblastei SSSR.) |
1977 |
| details |
Early Cambrian |
|
USSR |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |