1. James Ussher (1650: Anglican Archbishop)
 

2. Nick Steno (Danish Physician, 1669) sedimentary rocks: layers of sediments

Superposition -
 
 

Original Horizontality -
 
 

Original Lateral Continuity - deposited as laterally continuous beds unless they:
 

(a)
 

(b)
 

(c)
 

Late 1700's:

3. Abraham Werner, Neptunist model.

- Primitive rocks (oldest) -
 

- Transitional rocks (middle)
 

- Alluvium (young) - unconsolidated sediments.
 

- Many disagreed.
 
 

4. Georges Cuvier and Alexander Brogniart

- fossil record punctuated by extinctions - Catastrophies.
 
 

5. George Louis de Buffon, iron balls: Earth was 75-100,000 years old.
 
 
 
 

6. James Hutton, Scottish Physician wrote "Theory of the Earth"

Principle of Uniformitarianism -- same physical and chemical processes recognized in action today have operated throughout the history of the earth. No Catastrophism.
 
 
 
 

1800's

7. Charles Lyell wrote "Principles of Geology" (1830)

Principle of Cross-Cutting Relationships
 
 
 
 

Principle of Inclusions:
 
 
 
 
 

8. Louis Agassiz (Swiss biologist) - recognized that glacial erratics were from Scandinavia, not the Alps.
 
 

9. Lord Kelvin (British physicist) - measured heat conduction of rocks, heat flow in mines. Maximum age of the earth = 60-100 Ma.
 
 
 

1900's

10. Alfred Wegener (German meteorologist) careful geological and paleontological documentation of Continental Drift.
 
 
 
 

11. Sir Harold Jeffries (geophysicist) - proved mathematically that drifting continents were impossible.
 
 
 
 

12. Arthur Holmes (Scottish geologist)

- hot rocks can move: proposed that mantle convection is responsible for continental drift.
 
 
 

13. Harry Hess (Princeton geologist)

- young mid-ocean ridges: (1962) added Seafloor Spreading to Continental Drift story.
 
 
 

-- key is Observations over Interpretations.