| original |
Givetian |
|
Ohio |
Wicander,R. et al. Systematics and biostratigraphy of the organic-walled microphytoplankton from the Middle Devonian, (Givetian), Silica Formation, Ohio, USA. |
1981 |
| original |
Early Ashgillian |
Middle Ashgillian |
Canada(Anticosti Island) |
Jacobson,S.R. et al. Acritarch biostratigraphy of the Dicellograptus complanatus graptolite zone from the Vaureal form Ation, (Ashgillian), Anticosti Island, Quebec, Canada. |
1985 |
| original |
Early Visean |
Middle Visean |
Canada(Newfoundland) |
Utting,J. Palynology of the Lower Carboniferous Windsor Group and Windsor-Canso Boundary Beds of Nova Scotia, and their equivalents in Quebec, New Brunswick and Newfoundland. |
1987 |
| original |
Early Sheinwoodian |
|
Sweden |
Le H©riss©,A. Acritarchs and cysts of Prasinophycean algae of the Silurian of Gotland, Sweden. |
1989 |