A Trip Through Geologic Time. Chapter 10. Section 1- Fossils. Fossils are the preserved remains or traces of living things. Fossils provide evidence of how life has changed over time. How Fossils Form. Most fossils form when living things die and are buried by sediments.
The Relative Age of Rocks
Both types are always younger than the rocks around or beneath it.
that lived in shallow seas 500 mya to
their extinction 65 mya.
of shells and based on those differences
can ID rock layers which certain
ammonite fossils are found.