| original |
Ashgillian |
|
Oklahoma |
Loeblich,A.R.,Jr. et al. Some Middle and Late Ordovician microphytoplankton from Central North America. |
1978 |
| details |
Late Ordovician |
|
Kansas |
Wright,R.P. et al. Organic-walled microplankton in the subsurface Ordovician of Northeastern Kansas. |
1981 |
| details |
Ashgillian |
|
Oklahoma |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |
| details |
Late Ordovician |
|
Libya |
Grignani,D. et al. Palaeozoic and Mesozoic subsurface palynostratigraphy in the Al Kufrah Basin, Libya. (In: The Geology of Libya. M.J.Salem et al, editors) |
1991 |