Annulum |
Annulum squamaceum
|
USSR(Russian Platform) |
Early Cambrian |
Middle Cambrian |
Annulum |
Annulum squamaceum
|
Canada(Newfoundland) |
Middle Cambrian |
|
Annulum |
Annulum squamaceum
|
England |
Early Cambrian |
|
Anomaloplaisium |
Anomaloplaisium lumariacuspis
|
Gondwanaland |
Caradocian |
Ashgillian |
Aranidium |
Aranidium granulatum
|
Nd |
Nd |
|
Arbusculidium |
Arbusculidium
|
Nd |
Nd |
|
Arbusculidium |
Arbusculidium destombesii
|
Canada(Newfoundland) |
Late Cambrian |
Ordovician |
Arbusculidium |
Arbusculidium destombesii
|
USSR(Russian Platform) |
Late Cambrian |
Ordovician |
Arbusculidium |
Arbusculidium destombesii
|
England |
Tremadocian |
|
Arbusculidium |
Arbusculidium filamentosum
|
Canada(Newfoundland) |
Arenigian |
|
Arbusculidium |
Arbusculidium frondiferum
|
England |
Early Tremadocian |
|
Arbusculidium |
Arbusculidium mamillosum
|
Nd |
Nd |
|
Arbusculidium |
Arbusculidium rommelaerei
|
Canada(Newfoundland) |
Late Cambrian |
Ordovician |
Archaeodiscina |
Archaeodiscina umbonulata
|
Nd |
Nd |
|
Aremoricanium |
Aremoricanium squarrosum
|
Yemen |
Caradocian |
|
Aremoricanium |
Aremoricanium squarrosum
|
Gondwanaland |
Onnian |
Ashgillian |
Arkonia |
Arkonia
|
Nd |
Llanvirnian |
Llandeilian |