Earth History

In which layer might you expect to find a fossil of an early amphibian?

• Layer 3

• Layer 4

• Layer 5

• Layer 6

The diagram is a geological cross section of an area where a river has exposed a cliff of undisturbed rock layers. According to the diagram, which rock layer is the oldest?

• Q

• R

• S

• T

Which layer of rock was formed most recently?

• D

• C

• B

• A

Which rock layer is the oldest?

• 1

• 2

• 3

• 4

• 5

What type of fossil forms when sediments bury an organism and the sediments change into rock, the organism decays leaving a cavity in the shape of the organism?

• petrified fossils

• carbonized fossils

• mold fossils

• trace fossils

• cast fossils

What type of fossil forms when minerals soak into the buried remains, replacing the remains, and changing them to rock?

• petrified fossils

• carbonized fossils

• mold fossils

• trace fossils

• cast fossils

What type of fossil forms when a mold is filled with sand or mud that hardens into the shape of the organism?

• petrified fossils

• carbonized fossils

• mold fossils

• trace fossils

• cast fossils

What type of fossil forms when the entire organism or parts of the organism are prevented from decaying by being trapped in amber, ice, tar, or rock?

• carbonized fossils

• mold fossils

• trace fossils

• cast fossils

• preserved fossils

What type of fossil forms when mud and sand hardens to stone where a footprint, trail, or burrow of an organism was left behind?

• carbonized fossils

• mold fossils

• trace fossils

• cast fossils

• preserved fossils

What type of fossil forms when organisms or parts of organisms are pressed between layers of soft mud or clay that harden and squeeze all the decaying organism away leaving a carbon imprint in the rock?

• carbonized fossils

• mold fossils

• trace fossils

• cast fossils

• preserved fossils