era

1 - Reefs of the dinosaur era were dominated not by corals but by odd mollusks, which died off at the end of the Cretaceous from causes yet to be discovered.

2 - The typewriter is one of the most widely used machines in our modem era.

3 - During the cold war era scientists conducted experiments with sound waves in seawater.

4 - Ancient sea floor sediments show that a supernova exploded during the Pliocene era and may have caused a minor extinction event on Earth.

5 - Most of the world's Coal was formed during the Mississippian and Pennsylvanian Periods (286 to 360 MYA) of the Paleozoic Era (Ancient Life).