|process where the surface of the earth is worn away by the action of water, glaciers, winds, waves|
|seepage of water into soil or rock|
|Cambrian (kām'brē-ən, kām'-) Pronunciation Key
The first period of the Paleozoic Era, from about 540 to 505 million years ago. During this time warm seas and desert land areas were widespread, and animal life diversified rapidly during what is known as the Cambrian Explosion. See Chart at geologic time.