59:0.7 The ''[[marine]]-life era'' thus covers about one quarter of your [[planetary]] [[history]]. It may be subdivided into six long periods, each characterized by certain well-defined [[developments]] in both the [[geologic]] realms and the [[biologic]] [[domains]]. | 59:0.7 The ''[[marine]]-life era'' thus covers about one quarter of your [[planetary]] [[history]]. It may be subdivided into six long periods, each characterized by certain well-defined [[developments]] in both the [[geologic]] realms and the [[biologic]] [[domains]]. |