Soft Rock and Hard Rock

Digging DeeperGeological time chartPrevious

A geological time chart tells us the scientific names and time points given to different ages of geological history. The oldest times ("deep time") are shown at the bottom, and the most recent times (today) at the top. For example, any rock that formed between 359 million years ago and 299 million years ago is Carboniferous in age, no matter what type of rock it is or where in the world it comes from.