1. Paleogeography of North America Images by: Dr. Ron Blakey Professor of Geology Northern Arizona University http://jan.ucc.nau.edu/~rcb7/RCB http://jan.ucc.nau.edu/~rcb7/RCB.html (All images © Ron Blakey) Images incorporated into Powerpoint by Steve Perrin http://www-personal.umich.edu/~sperrin/gallery.html

2. Late Precambrian 550 Ma (Million Years Ago)

3. Middle Cambrian 510 Ma

4. Late Cambrian 500 Ma

5. Early Ordovician 485 Ma

6. Middle Ordovician 470 Ma

7. Late Ordovician 450 Ma

8. Early Silurian 430 Ma

9. Late Silurian 420 Ma

10. Early Devonian 400 Ma

11. Middle Devonian 385 Ma

12. Late Devonian360 Ma

13. Early Mississippian 345 Ma

14. Late Mississippian 325 Ma

15. Early Pennsylvanian 315 Ma

16. Late Pennsylvanian 300 Ma

17. Early Permian 290 Ma

18. Middle Permian 275 Ma

19. Late Permian 260 Ma

20. Early Triassic 245 Ma

21. Middle Triassic 230 Ma

22. Late Triassic 210 Ma

23. Early Jurassic 195 Ma

24. Early Jurassic 180 Ma

25. Middle Jurassic 170 Ma

26. Late Jurassic 150 Ma

27. Early Cretaceous 140 Ma

28. Early Cretaceous 130 Ma

29. Early Cretaceous 115 Ma

30. Late Cretaceous 100 Ma

31. Late Cretaceous 85 Ma

32. Late Cretaceous 75 Ma

33. Cretaceous-Tertiary 65 Ma

34. Paleogene Paleocene 60 Ma

35. Paleogene Eocene 50 Ma

36. Paleogene Eocene 40 Ma

37. Paleogene Oligocene 25 Ma

38. Neogene Miocene 15 Ma

39. Neogene Miocene 8 Ma

40. Neogene Pliocene 3 Ma

41. Quaternary Glacial 126,000 Years Ago

42. Present

43. Description