Geological periods

The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.

The Cretaceous (pronunciation: /krᵻˈteɪʃəs/, krə-TAY-shəs) is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago (Mya) to the beginning of the Paleogene Period 66 Mya.

The Cryogenian (pronunciation: /kraɪoʊˈdʒɛniən/, from Greek cryos "cold" and genesis "birth") is a geologic period that lasted from 720 to 635 million years ago.

The Jurassic (pronunciation: /dʒuːˈræsɪk/; from Jura Mountains) is a geologic period and system that spans 56.

The Ordovician (pronunciation: /ɔːrdəˈvɪʃən/) is a geologic period and system, the second of six of the Paleozoic Era, that spans 41.

The Paleogene (pronunciation: /ˈpæliːədʒiːn/ or /ˈpeɪliːədʒiːn/; also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago (Mya) to the beginning of the Neogene Period 23.

The Permian is a geologic period and system which spans 46.

The Quaternary Period (pronunciation: /kwəˈtɜːrnəri/) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS).

The Silurian is a geologic period and system spanning 24.

An ice age is a period of long-term reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.

Tertiary is the former term for the geologic period from 66 million to 2.