Across
- 2. gives the age of rock layers using numbers
- 3. 18th century farmer and physician who developed the idea of uniformitarianism
- 6. states that sedimentary rocks will remain in horizontal layers unless acted upon by an outside force
- 10. the time it takes for half of a radioactive sample to decay
- 12. states that older rock layers are on the bottom and younger rock layers are on top
- 13. remains of living organisms in hardened tree sap
Down
- 1. evidence of past animal movement such as footprints, tracks or borings
- 4. states that the same forces that shaped Earth millions of years ago are the same forces that shape Earth today
- 5. breaks in the rock record
- 7. a fossil that is used to establish the age of rock due to the short time it lived
- 8. the study of fossils
- 9. the remains or traces of animals or plants
- 11. states the age of rock layers in terms of older or younger