1. (a.) Of or pertaining to a division Of the Silurian formation, corresponding in general to the Lower Silurian Of most authors, exclusive Of the Cambrian.
2. (n.) The Ordovician formation.
| Ordovician 1. (a.) Of or pertaining to a division Of the Silurian formation, corresponding in general to the Lower Silurian Of most authors, exclusive Of the Cambrian. 2. (n.) The Ordovician formation. | |