The Sh'dama Age was a historical period on the planet Bajor.
Kejelious was an important material in this age. Jake Sisko was told of the Sh'dama Age age by Eivos Calan in 2376. (DS9 novel: Avatar, Book One)
Later in 2376, Jake's knowledge of the Sh'dama Age allowed him to identify kejelious on the Eav'oq homeworld. (DS9 novel: Rising Son)