Across
- 3. Age of Early Life
- 4. unit of geological time during which a rock series is deposited.
- 5. ion the operation of distributing objects into classes or groups
- 7. a branch of geology concerned with the study of rock layers (strata) and layering (stratification)
- 8. a scientist who studies the structure, composition, and history of Earth.
- 9. an animal without a backbone
- 10. a representation of time based on the rock record of Earth.
Down
- 1. Long span of geologic time
- 2. one of the principles of geology scientists use to determine the relative ages of rock strata, or layers
- 6. a scientist who specializes in the study of life forms that existed in previous geologic periods, as represented by their fossils