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Geolocation
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Author - title
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Year
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| details | Early Tremadocian | Early Ludlovian | Belgium | Martin,F. The acritarchs from the Belgian Ordovician and Silurian. Determination and stratigraphic value. | 1968 |
| details | Early Ordovician | USSR(Russian Platform) | Andreeva,E.M. et al. Palaeopalynology. (Three Volumes: Volume I: Methods. Volume II: Complexes of palynomorphs of the Precambrian-Holocene of the USSR. Volume III: Figures and Plates. Editor-I.M. Pokrovskaya) | 1966 |