the longest division of geological time
a major division of geological time that is usually divided into periods
unit of geologic time into which eras are subdivided, they are divided into epochs
the shortest division of geologic time marked by distinctive features, events, and organisms.
geologic time scale
a chronological arrangement of geologic events and life forms divided into units
the part of geologic time from the formation of the Earth through the rise of simple life forms
the part of geologic time when invertebrates, fishes, amphibians, reptiles and ferns were dominant
the part of geologic time when dinosaurs flourished and then became extinct
the current era of geologic time that began about 66 million years ago; it is known as the "Age of Mammals"