| original |
Givetian |
|
New York |
Wood,G.D. Some Middle Devonian, (Givetian), chitinozoans and acritarchs from New York State. Preliminary results. |
1986 |
| details |
Middle Devonian |
Late Devonian |
Canada(Ontario) |
Eley,B.E. et al. Cherts of Southern Ontario |
1989 |
| details |
Frasnian |
|
Worldwide |
Colbath,G.K. Palaeobiogeography of Middle Palaeozoic organic-walled phytoplankton. (In: Palaeozoic Palaeogeography and Biogeography. W.S.McKerrow and C.R.Scotese, editors) |
1990 |
| details |
Early Wenlockian |
|
Sweden(Gotland) |
Munnecke,A. et al. Scanning electron microscopy of polished, slightly etched rock surfaces: A method to observe palynomorphs in situ. |
1996 |