Ordovician period.

The Ordovician is a geological period and system, the second of six of the Paleozoic Era.

·Cambrian

·Ordovician

·Silurian

·Devonian

·Carboniferous

·Permian

The Ordovician was named after the celtic tribe of the Ordovices, defined by Charles Lapworth who was working on celtic lands.

The ordovician was separated in three stages:

• Early epoch : Tremadocian and Arenig.
• Middle epoch: Llanvirn and Llandeilo.
• Late epoch : Caradoc and Ashgill.

In the Ordovician there were four continents: Laurentia, Siberia, Baltica and Gondwana. All were quite small except Gondwana; it was the greatest of all in this period.The weather was warm and tropical. In fact in many places was very high temperatures of 40-50°C and rarely up to 60°C. The Sea levels were very high during this period and the amount of oxygen in the atmosphere was low so marine life were the most salient new life. Abounded animales like: trilobites, graptolites, brachiopods, bivalves, etc, and the marine fungui was very common. The firs land plants appeared like liver.


The Ordovician ends with a big glaciation caused by the decrease of the carbon dioxide in the atmosphere.