precambrian

adj

1. (informal, not-comparable)Relating to the time and geology dated before the Phanerozoic

   “When you look at a Precambrian trilobite in the lobby of a New York bank, it is difficult to speculate about its primeval environment.”

name

1. The Precambrian supereon; spanning from the formation of the Earth around 4.6 billion years ago to the emergence of hard-shelled creatures 541 million years ago.