Name:________________________________
Period:__________
Earth History review
1. Why are sedimentary rocks often formed in large, flat layers?
2. What must occur for loose sediments to become a rock?
3. How do sediments carried by a river act when they reach a lake?
4. According to scientific assumptions, which rock layers in the Grand Canyon will
usually contain older fossils?
5. What evidence do scientists have that supports the idea that Earth’s surface has
changed over time?
Use the drawing to answer the next three questions. Assume only the
fossilized bones of these organisms
remain.
6. Where did the sediments that formed these
rocks most likely collect?
7. How does the age of the fossils in rock
layer B compare with the fossils in rock
layer A?
8. Which layer contains fossils more closely
related to fish found on Earth today?
9. What conditions would allow older sedimentary rock to lie in layers above
younger sedimentary rock?
Use this diagram to answer the next two questions:
10. Which location shows older rocks above younger rock
11. Based on the diagram, what force most likely created the changes to the bottom
three layers?
12. Which of the following is a typical location where a bone or shell could become
petrified?
13. In a region of Wyoming covered by rolling hills, small lakes, and dry gulches, a
petrified shark’s tooth was found. What does this fossil indicate about the
geological history of this region?
14. In the dry and hilly region of southeast Utah, many fossil remains have been
uncovered. Trilobite casts, petrified bones of alligators, and preserved dinosaur
footprints, were all found in the same location, but in different rock layers. What
do these fossil remains tell about the history of this region?
15. Why do recently deposited rock layers contain fossils more like animals that are
alive today?