Geologic Time Scale

Front

Current geological period?

Back

Cenozoic Era

Front

First appearance of jellyfish?

Back

Precambrian

Front

Time period of Pangaea's appearance?

Back

Paleozoic

Front

Dinosaurs, small mammals, and birds existed in the Mesozoic era.

Back

Mesozoic

Front

Fossils that are abundant, recognizable, short-lived, and widespread?

Back

Index fossils

Front

Preserved remains of ancient plants and animals?

Back

Fossils

Front

Law of Superposition: Younger rock layers are above older layers.

Back

Correct Answer: Younger rock layers are on top of older rock layers.

Front

Longest era, covering 88% of geologic time?

Back

Precambrian

Front

Absolute age of a rock layer or fossil indicates:

Back

The 'exact' age determined by radiometric dating.

Front

End of an era and life for groups of organisms?

Back

Mass extinction