| original |
Llandeilian |
|
Oklahoma |
Loeblich,A.R.,Jr. et al. Some Middle and Late Ordovician microphytoplankton from Central North America. |
1978 |
| details |
Llandeilian |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |
| details |
Late Llandeilian |
Middle Caradocian |
USSR(Estonian SSR) |
Uutela,A. et al. Ordovician acritarchs from the Rapla borehole, Estonia |
1991 |
| details |
Middle Ordovician |
Late Ordovician |
Iran |
Ghavidel-Syooki,M. Acritarch biostratigraphy and palaeogeography of Lower Palaeozoic rock units at Southwestern Kashmar City, Central Iran. |
1998 |