NSES Content Standard D   Earth and Space Science: Earth's history  Grades 5-8, page 160  Fossils provide important evidence of how life and environmental conditions have changed.

 
Benchmark 4C The Physical Setting: Processes that Shape the Earth
Grades 6-8, page 73
Thousands of layers of sedimentary rock confirm the long history of the changing surface of the earth and the changing life forms whose remains are found in successive layers. The youngest layers are not always found on top, because of folding, breaking, and uplift of layers.