Name:________________________________
Period:__________
Earth History review
1. Why are sedimentary rocks often formed in large, flat layers?
Sediments usually collect on Earth’s surface as flat deposits.
2. What must occur for loose sediments to become a rock?
minerals from water flowing through them must cement the sediments together
3. How do sediments carried by a river act when they reach a lake?
they spread out on the lake bottom
4. According to scientific assumptions, which rock layers in the Grand Canyon will
usually contain older fossils?
In the rock layers located deep in the canyon.
5. What evidence do scientists have that supports the idea that Earth’s surface has
changed over time?
fossils of rainforest plants in areas that are deserts today.
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?
on a shoreline
7. How does the age of the fossils in rock
layer B compare with the fossils in rock
layer A?
the fossils in rock layer A are younger.
8. Which layer contains fossils more closely
related to fish found on Earth today?
Layer A, it is the newest and has the most
recent fossils.
9. What conditions would allow older sedimentary rock to lie in layers above
younger sedimentary rock?
areas of faulting and folding
Use this diagram to answer the next two questions:
10. Which location shows older rocks above younger rock
B
11. Based on the diagram, what force most likely created the changes to the bottom
three layers?
compression causing folding
12. Which of the following is a typical location where a bone or shell could become
petrified?
submerged in shallow water or mud.
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?
it was once covered by an ocean
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?
the Earth’s surface and climate has changed over time.
15. Why do recently deposited rock layers contain fossils more like animals that are
alive today?
The fossils are the most recent ancestors of today’s animals.