Grade Level: 4th Grade
Sedimentary rock layers are found in places all around the world. They can provide useful clues to the past. Sometimes a waterway cuts through the layers revealing a geologic record of the past. In other locations, scientists must dig trenches to see the layers. As the lower layers generally formed first, they are the oldest. Fossils within the rocks may allow some layers to be dated with accuracy. In other locations, clues may be sparse.
Martinez, Elizabeth, "Earth Systems - Patterns in the Rocks" (2019). Model NGSS Lessons: 4th - 5th Grade. 3.