Geologic Time

1. the preserved remains or evidence of past living organisms.
3. the principle that if one geologic feature cuts across another feature, the feature that it cuts across is older.
5. principle that sediments are deposited in large, continuous sheets in all lateral directions.
8. a method used by geologists to fill in the missing gaps in an area’s rock record by matching rocks and fossils from separate locations.
9. a chart that divides Earth’s history into different time units based on changes in the rocks and fossils
11. age the numerical age, in years, of a rock or object.
12. the extinction of many species on Earth within a short period of time.
13. bed a rock or sediment layer with distinctive characteristics that make it easily identifiable in correlation.
14. a fossil representative of a species that existed on Earth for a short length of time, was abundant, and inhabited many locations.
15. a piece of an older rock that becomes a part of a new rock.

2. the principle that in undisturbed rock layers, the oldest rocks are on the bottom.
4. surfaces where rock has eroded away, producing a break, or gap, in the rock record.
6. a principle stating that geologic processes that occur today are similar to those that occurred in the past.
7. the age of rocks and geologic features compared with other nearby rocks and features.
10. principle that most rock-forming materials are deposited in horizontal layers.