Across
- 7. determined by newer ones of older ones. How old the rock is (not exact)
- 9. 65 million years ago through today (what we are currently in)
- 10. something no longer exists
- 11. 541 million years ago through 251.9 million years ago
- 13. fossil that is used to estimate what era of time a certain place is
- 14. 251.9 million years ago through 65 million years ago
- 15. the process by which all substances of plants and animals decay except carbon leaves a carbon film on sedimentary rock happens mostly with plants and fish
Down
- 1. the original matter is all preserved
- 2. you can tell the age of a rock by how far under the layers it is
- 3. the organism turns into rock over time
- 4. an animal can become trapped in tar and the whale body can be preserved. Freezing can also trap whole animals. Mammoth’ bodie have been found with skin, hair, and even organs
- 5. original minerals are replaced
- 6. fossils that are preserved in tree sap this even preserves the DNA of the animal
- 8. footprints, track, burrows, feces, borings, provides indirect evidence of life in the past rather than the body of the animal itself.
- 12. some unstable isotopes of some elements decay at a known rate into daughter products