Carboniferous
Carboniferous period

It lived in the late Carboniferous period, 306 million years ago.

Later, during the Carboniferous period, sea levels again began to rise and fall.

The rock is estimated to have risen some 350 million years ago during the lower Carboniferous period.

It lived 300 million years ago during the late Carboniferous period.

Seas continued to cover the state into the Carboniferous period.

It lived during the Carboniferous period, about 350 million years ago.

However, the state would once more be submerged during the early part of the Carboniferous period.

It's supposed to have gone extinct during the Carboniferous period.

The Carboniferous period actually came rather late in the planet's history.

The sea remained in place during the early part of the Carboniferous period.