Across
- 4. The system of time measurement involving the information of and changes to the earth
- 8. a subdivision of a period
- 9. a subdivision of an eon
- 11. refers to the info provided by all of the discovered fossils throughout Earth's history
- 12. a common fossil found in many areas from a specific time used to help identify the age of other formations
- 13. remains or impression of an organism preserved or in petrified rock
- 15. a fossil that forms when organic material is trapped in ice, rock, amber, or tar
- 17. occurs when a species (organism) dies out and no longer lives on the planet
- 18. states that younger rock is found above older rock when comparing sedimentary rock layers
Down
- 1. method of determining the age based on measuring radioactive measuring
- 2. The branch of science involving physical composition and history of the earth
- 3. a fossil that forms when minerals solidify into the rock around the shape of the original organism
- 5. a fossilized piece of evidence of an organism's activity
- 6. fossil- a fossil that forms when a mold is filled with sediment and hardens into the shape of that organism
- 7. fossil- fossil that forms when organic material is pressed between layers of rock
- 10. a subdivision of an era
- 14. Very large division of geologic time; usually referred to as the longest division of time
- 16. determining the age of a rock based on the surrounding evidence