This document discusses different types of fossils used for dating rock layers and determining geologic timescales. It identifies relative dating as determining the order of events without specific time assigned, while absolute dating provides specific numerical ages using radiometric dating. It also lists different index fossils such as trilobites, graptolites, and fusulinids that were used to differentiate periods in the geologic column.

2. -
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3. Relative
age)
• Absolute
time)

4. Fossil)

5. index fossil) :
trilobite)
(graptolite)
fusulinid)

6. Body fossils

7. 2.
Trace fossils
•

8. kingdom phylum
division
class order family
genus species
1.
Invertebrate fossils
2.
Vertebrate fossils
3. Plant fossils
4. Trace fossils