Discussion: Grand Canyon History

Historians use artifacts  to describe and explain events in history. But how do scientists describe and explain events in Earth's history?They study rocks. The rock layers provide a record of the Earth's history. By examining each layer, scientists get information about past events. Then they use the principles of geology to describe and explain the complete history of an area. How is the history of the Grand Canyon explained?

Look at Arnold's post:

• Describe one of Steno's principles in your own words.
• Use this principle to explain one aspect of the geologic history of the Grand Canyon.