Here's why:
* Fossils as Time Markers: Fossils of certain species lived during specific periods in Earth's history. These "index fossils" act like time markers, allowing geologists to correlate rock layers across different locations.
* Correlation: When you find the same index fossils in rock layers at different locations, it suggests those layers formed around the same time. This process of matching rock layers based on fossils is called correlation.
Example: Imagine you find a trilobite fossil in a rock layer in New York and a similar trilobite fossil in a rock layer in California. This suggests that those two rock layers likely formed during the same period, even though they are geographically distant.
Let me know if you'd like to explore more about fossils and their role in understanding Earth's history!
