Comment: 05:12 - 06:06 (00:54)
Source: Annenberg/CPB Resources - Earth Revealed - 10. Geologic Time
Keywords: "James Hutton", land, erosion, life, stream, sand, gravel, sediment, "sedimentary rock", uplift, water
Our transcription: An important question intrigued Hutton.
He saw that land is worn down in many places by the destructive forces of erosion.
How then was it possible any land was left to support life?
He believed there must be an undiscovered force building up the land, which counteracts the processes wearing it away.
He began searching for evidence of this force, and soon found it.
Hutton observed that streams washed sand and gravel into the sea, where the sediment accumulated in offshore deposits.
He found similar material in the form of ancient sedimentary strata, tilted and raised above sea level.
Surely, Hutton thought, these layers must also have formed under water, then risen to become new land.
Geology School Keywords