Ordovician period

They have changed little in appearance since the Ordovician period, 450 million years ago.

Their fossil record extends back to the Ordovician period (460 million years ago).

This also marks the end of the Ordovician period.

This order dates back to the lower Ordovician period.

Similar conditions and wildlife remained in place during the early part of the ensuing Ordovician period.

The earth's climate 450 million years ago (the Ordovician period) is one of the big unknowns.

As time passed there was a possible lowering of local temperatures in the succeeding Ordovician period.

The earliest fossil of fungi appears about 460 million years ago in the Ordovician period.

They survived at least until the Ordovician period.

Missouri had a varied fauna during the ensuing Ordovician period.

The Ordovician period is the second of the Paleozoic era.

This trend would continue into the Ordovician period.

Two land masses collided at the end of the Ordovician Period about 466 million years ago.

Lingula is known to have existed since the early Ordovician period.

This makes it easier to place many more species in time relative to the beginning of the Ordovician Period.

By the Ordovician period the gastropods were a varied group present in a few aquatic habitats.

The fossils are of primitive fish and date back 450 million years to the Ordovician Period.

Marine deposition took place throughout most of this and the succeeding Ordovician Period.

But mostly in the Ordovician Period, this zone was above water and eroding.

We have ancient rocks from the Ordovician Period, 430 million to 500 million years ago.

They lived during the late Cambrian period to the Ordovician period.

The lake is located on paleozoic limestone of the Ordovician period.

The limestone has been claimed to be Ordovician period or Cretaceous rock.

If one looks closely, Ordovician period gastropod fossils can be found in the limestones.

In the ensuing Ordovician period Indiana was still submerged by the sea.