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Name_________________________
PS/ES Per___
Date ___________________
Mr. Landsman
INDEX FOSSILS INSERT
Complete BEFORE procedure “B” on Matching Rock Layers Lab
Concept: Index fossils are useful for correlation because they are;

Widespread: found in many layers spread horizontally. This is
important because correlation involves matching rocks that may be far
away from each other.

Short-lived: found only in a narrow range of geologic time (do not
extend vertically in a rock column). This is important because
correlating rocks by age requires a narrow range of geologic time.


Easily recognized: so you can tell what they are
Well preserved: bones and shells preserve better than goo. Jellyfish
and worms don’t usually make good index fossils.
_______________________ and ___________________ are better
types of organisms.
Task: The rectangles on the cut-out sheet represent fossil-bearing rock layers
from different areas. Cut out the rectangles. Arrange them so that fossils match
side by side. Fossil “G” is the oldest (superposition). The layers should progress
upwards through time. When finished, have your column verified then continue
with the following questions.
1. Briefly state the principle of SUPERPOSITION:
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2. Rate fossil “W” as an index fossil. (Good // Bad)
Explain the logic behind your rating. What’s good/bad about it?
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3. Indicate the best index fossil ______________.
Explain why this fossil would be best for correlation. Be specific and refer to the
column you created.
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4. What other organisms from your columns make good index fossils?
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5. List the fossil letters from oldest to youngest.
_____ _____ _____ _____ _____ _____ _____ _____ _____ _____ ____