The Katian is the second stage of the Upper Ordovician. It is preceded by the Sandbian and succeeded by the Hirnantian stage. The Katian began {Geologic Ages Inline|Katian} million years ago and lasted for about 7.8 million years until the beginning of the Hirnantian {Geologic Ages Inline|Hirnantian} million years ago. ==Naming== The name Katian i...