Illustrations

Plates (following page 52)

1. Parts of the St. Elias Range and Malaspina Glacier. 2. Hubbard Glacier entering Disenchantment Bay, Yakutat Bay area. 3. Mount Crillon (12,726 feet) and Brady Glacier. 4. Mount Crillon (12,726 feet) viewed across Johns Hopkins Inlet. 5. Nunatak Fiord, Yakutat Bay. 6. Part of the Chugach Range, including Mount Witherspoon (12,023 feet). 7. Perspective diagram of Upper Cook Inlet area showing setting of Anchorage. 8. and the Wrangell Mountains. 9. Sourdough Peak in the southern foothills of the Wrangell Mountains. 10. Cliffs of Triassic limestone in the southeastern Wrangell Mountains. 11. Mount McKinley from the northeast. xii Illustrations

12. Part of the Range, including Mount McKinley. 13. Eocene coals and sandstones on Lignite Creek, near Healy. 14. Recessional moraines on the north side of Iliamna volcano. 15. Caldera of Katmai volcano. 16. Head of the Valley of Ten Thousand Smokes. 17. Dacite dome on the south flank of Trident volcano. 18. Shishaldin volcano, Unimak Island. 19. Placer gold mining near Fairbanks. 20. Typical upland terrain, northern . 21. Mount Doonerak from Amawk Mountain, Brooks Range. 22. Highest part of the Brooks Range. 23. Polygonal ground and thaw lakes near Skull Cliff, southwest of Barrow.

Maps

facing page 1. Physiographic provinces of Alaska. 4 2. Southeastern Alaska. 12 3. area, Wrangell Mountains, Copper River plateau, Talkeetna Mountains, Cook Inlet and Susitna lowland, and Alaska Range. 20 4. -. 68 5. Lowlands and plains of interior and western Alaska; interior high- lands of western and eastern Alaska; Seward Peninsula. 76 6. Brooks Range and Arctic Slope. 116

Figures

1. Evolution of Okmok caldera, Umnak Island. 62 2. Present areas occupied by glaciers and by permafrost, and areas formerly covered by glaciers at the time of their maximum spread during the Pleistocene period. facing page 80 3. Development of the Bering Sea Land Bridge. 134