1. Question of the Day How can you use fossils to determine relative ages of rock layers?
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2. Fossils
Any remains, trace, or imprint of a living thing preserved in Earth’s crust.
Most fossils are found in which rocks?
Metamorphic
Igneous
Sedimentary

4. Then and Now

6. Correlation
Matching up rocks or geologic events from different locations by similar age

8. Distributed over wide area
Index Fossils
Lived for short time
Distributed over wide area
Abundant
Eurypterid

9. Key Beds
Rock layer that is unique and easily recognizable.
Deposited over a short time period
Widespread
Ex. Volcanic ash, meteorite deposits