| original |
Ordovician |
|
Baltic |
Eisenack,A. The microfossils of Osteekalke (Ordovician) 3. Graptolite, Melanoskelton, Sponge, Radiolarian, problematic and Supplements on Foraminifera and phytoplankton |
1971 |
| details |
Late Ludlovian |
|
E.Germany |
Eisenack,A. Contribution to acritarch research. |
1974 |
| details |
Early Paleozoic |
|
Nd |
Cramer,F.H. et al. Lower Paleozoic acritarchs. |
1979 |
| details |
Ordovician |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |