Geologic Time is a crucial concept to understanding the history of the earth—including the evolution of life. Many different representations of the timeline have been created, and many approaches ...

THE present short article is a reversion to an aspect of the subject of geologic time which I had thought to be settled, and to require no further research or controversy. In my review of Mr ...

An Index fossil is any animal or plant preserved in the rock record of the Earth that is characteristic of a particular span of geologic time or environment. We will look at a few index fossils and ...