Across
- 2. Rocks formed by the cooling and solidifying of molten materials.
- 4. Continuous process by which rocks are created and changed from one form to another.
- 5. Rocks that have been formed by sediments, especially sediment carried by water, ice and wind.
- 8. The remains, traces or imprints of once living things.
- 11. A fossil formed when a plant or animal dies then minerals enter the cavity and then become solid
- 13. A calendar of earth’s geologic history defined by major changes that happen on earth.
- 18. A type of fossil made up of a thin layer of carbon
- 19. The slow change of living things through time
- 20. The true age of a rock or fossil and helps scientists know the number of years ago a rock layer formed.
- 21. Fossils used to define and identify a particular period of time that lived in many places for a short period of time.
Down
- 1. A group of similar living things that can reproduce
- 3. The theory that all changes on earth that are happening today are the same as have happened in the past.
- 6. A period of time in geologic time that is relatively short, dividing the different Periods
- 7. A type of fossil were the remains of a dead organism is left preserved
- 9. Rocks that have been formed from extreme heat and pressure.
- 10. Coal, oil or natural gas that is produced by the very gradual decaying of animals or plants over millions of years.
- 12. the comparison of one rock or fossil to another to determine which one is older or younger
- 14. A period of time in geologic time that is relatively long, dividing the different Eons
- 15. The process by which only plants and animals that can survive in their environment will continue to live
- 16. The indent made when an animal, plant, or other organism dies and is covered by sediment where a cavity is made.
- 17. The order in which sedimentary rock layers are made, older layers are lower and younger layers are on top.