What is "untimed"

Usage examples of "untimed".

Then followed various untimed periods, during which animal life rose by degrees from mollusk and jellyfish, by plesiosaurus and pterodactyl, horrible monsters, hundreds of feet in length, whose tramp crashed through the woods, or whose flight loaded the groaning air, to the dolphin and the whale in the sea, the horse and the lion on the land, and the eagle, the nightingale, and the bird of paradise in the air.