Question

What are ordovician?
please explain it

Answer 1

The Ordovicianis a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago  to the start of the Silurian Period 443.8 Mya.

Answer 2

The Ordovician is the second period of the Paleozoic era. It lasted from about 485.4 million years (mya) to 443.4 mya.[1] It follows the Cambrian period and is followed by the Silurian period.

The Ordovician was named after the Welsh tribe of the Ordovices. It was defined by Charles Lapworth in 1879. He recognized that the fossils in the disputed strata were different from those of the Cambrian or the Silurian. Therefore, he reasoned, they should be placed in a period of their own.

Recognition of the Ordovician period was slow in Britain, but elsewhere it was quickly accepted. In 1906 it was adopted as an official period of the Paleozoic era by the International Geological Congress.

The Ordovician ended with a series of extinction events that, together amount to the second greatest extinction of the Phanerozoic. This was the End–Ordovician extinction event.