Across
- 1. a formed pre-existing rocK or pieces of once-living organisms.
- 3. evolved toward those of the present.
- 7. an object made by shaping molten metal or similar material in a mold.
- 9. a major division of time that is a subdivision of an eon and is itself subdivided into periods.
- 11. The approximate age determination of rocks, fossils or minerals made by comparing whether the material is younger or older than other surrounding material.
- 13. a part or length of material formed by pushing a material through a die with a particular cross-section.
- 14. form out of malleable material.
- 15. the gradual development of something, especially from a simple to a more complex form.
- 16. when minerals replace the structure of an organism.
- 18. the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
- 19. a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.
Down
- 2. an organism outline of a fossil.
- 4. a surface of contact between two groups of unconformable strata.
- 5. the time taken for the radioactivity of a specified isotope to fall to half its original value.
- 6. a fossil that is useful for dating and correlating the strata in which it is found.
- 8. a science dealing with the life of past geologic periods as known from fossil remains To many Americans
- 10. (of a rock formation) be broken by a fault or faults.
- 12. a volcano not having erupted in recorded history.
- 15. the weather, especially strong winds, heavy rain, and other kinds of bad weather.
- 17. a division of time that is a subdivision of a period and is itself subdivided into ages, corresponding to a series in chronostratigraphy.