| original |
Late Tremadocian |
Early Arenigian |
Italy(Sardinia) |
Pittau Demelia,P. Tremadocian (Early Ordovician) acritarchs of the Arburese Unit southwest Sardinia, (Italy). |
1985 |
| details |
Tremadocian |
|
Austria |
Reitz,E. et al. Lower Ordovician acritarchs of the northern Graywacke Zone, (Eastern Alps). |
1989 |
| details |
Late Tremadocian |
Early Arenigian |
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |
| details |
Tremadocian |
|
Austria |
Reitz,E. et al. Palynological evidence for Lower Ordovician rocks (Tremadoc and Arenig) in the northern Greywacke zone (Eastern Alps) |
1992 |
| details |
Early Ordovician |
|
Italy(Sardinia) |
Sarjeant,W.A.S. et al. The Micrhystridium and Veryhachium Complexes (Acritarcha: Acanthomorphitae and Polygonomorphitae): A taxonomic reconsideration. |
1994 |
| details |
Early Ordovician |
|
Italy(Sardinia) |
Stancliffe,R.P.W. et al. The acritarch genus Veryhachium Deunff,1954, emend., Sarjeant and Stancliffe,1994: A taxonomic restudy and a reassessment of its constituent species. |
1994 |