1. Ch.3, Sec.1 – Earth’s Story & Those Who First Listened
The Principle of Uniformitarianism
- James Hutton, a Scottish scientist, was the founder of modern geology, based upon his research in 1788
- Hutton observed that processes we observe today, like erosion & deposition, remain uniform over time
- his idea, uniformitarianism, states that geologic processes that occurred in the past can be explained by current geologic processes
- in the 1700s, people believed the Earth was thousands of years old, not millions, which is what Hutton believed

2. Ch.3, Sec.1 – Earth’s Story & Those Who First Listened

3. Ch.3, Sec.1 – Earth’s Story & Those Who First Listened
- Hutton observed layers of rocks that were vertical & horizontal at Siccar Point in Scotland
- Siccar Point would have taken millions of years to have formed, not thousands which is what was stated in religious scriptures
- most scientists at the time supported the idea of catastrophism, which is a principle that states that geologic change occurs suddenly
- supporters of catastrophism believed all geologic landforms were created by catastrophes very quickly, not slowly

4. Ch.3, Sec.1 – Earth’s Story & Those Who First Listened
- in the 1830s, British geologist Charles Lyell reintroduced more evidence to show support for uniformitarianism
Modern Geology – A Happy Medium
- scientists now believe that both theories have played a role in geologic processes, with most coming very slowly
- huge craters have been found all over Earth to help support the idea of catastrophism affecting geological processes and possibly killing all of the dinosaurs 65mya

5. Ch.3, Sec.1 – Earth’s Story & Those Who First Listened
Barrington Crater in Arizona

6. Ch.3, Sec.1 – Earth’s Story & Those Who First Listened
- dinosaur extinction is a good example of catastrophism
Chicxulub Crater, Mexico

7. Ch.3, Sec.1 – Earth’s Story & Those Who First Listened
Paleontology – The Study of Past Life
- the history of the Earth would be incomplete without a knowledge of all of the organisms that have lived on the planet
- the science involved with the study of past life is called paleontology
- paleontologists study fossils of animal remains & paleobotanists study fossils of plants