Geologic Time Scale

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Across
  1. 1. A subdivision of an era in the geologic time scale
  2. 6. Rock formations that show Earth’s history over time
  3. 7. Supercontinent that included nearly all landmasses
  4. 10. Dominant land animals during the Mesozoic Era
  5. 12. Marine arthropod common in Paleozoic oceans
  6. 14. Process that wears away Earth’s surface
  7. 16. Era known for the development of early fish, insects, and land plants
  8. 17. Long-term weather conditions of an area
  9. 20. Period of widespread ice coverage on Earth
  10. 21. Rock type where most fossils are found
  11. 22. Era often called the Age of Reptiles
  12. 24. Vertebrates that live both on land and in water
  13. 25. Earliest and longest span of Earth’s history before complex life appeared
  14. 26. Cold-blooded vertebrates that dominated the Mesozoic Era
Down
  1. 2. A large division of geologic time made up of periods
  2. 3. Current era known as the Age of Mammals
  3. 4. Determining whether rocks are older or younger
  4. 5. Large pieces of Earth’s crust that move slowly
  5. 8. Change in living organisms over long periods of time
  6. 9. Earliest vertebrates found in ancient oceans
  7. 11. Trait that helps an organism survive in its environment
  8. 13. Event in which many species die out at the same time
  9. 14. A smaller division of geologic time within a period
  10. 15. Preserved remains or traces of ancient organisms
  11. 17. Movement of Earth’s continents over time
  12. 18. Organisms that first moved onto land during the Paleozoic
  13. 19. Opening in Earth’s surface where magma escapes
  14. 22. Animals that became dominant in the Cenozoic Era
  15. 23. Rapid loss of many species across Earth