ordovician

The Ordovician period was a time of great diversification of marine life.

Many trilobites lived during the Ordovician period.

The Ordovician period lasted from about 485 to 444 million years ago.

Fossils from the Ordovician period provide valuable information about ancient ecosystems.

The Ordovician period followed the Cambrian period.

Some of the earliest fish evolved during the Ordovician period.

The climate during the Ordovician period was warmer than today.

The Ordovician period is named after a Celtic tribe called the Ordovices.

The Ordovician period ended with a mass extinction event.

Scientists study the rock layers from the Ordovician period to learn about Earth's history.