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From
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Geolocation
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Author - title
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Year
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| original | Late Cambrian | USSR(Pre-Baltic) | Timofeev,B.V. Ancient flora of the Prebaltic Region and its stratigraphic significance | 1959 | |
| details | Tremadocian | Spain | Wolf,R. The Lower and Upper boundary of the Ordovician System of some selected regions, (Celtiberia, Eastern Sierra Morena) in Spain. Part 1: The Lower Ordovician Sequence of Celtiberia. | 1980 |