1743-1826 1796-1878 19thcentury ambition american-west astor astoria benjaminlouiseulaliede biography bonneville columbia-river descriptionandtravel discoveriesingeography discoveryandexploration early-american-frontier exploration explorers fur-trade furtrade history indiansofnorthamerica jefferson john-jacob-astor johnjacob lewis-and-clark-expedition lost-pacific-empire manifest-destiny native-americans oklahoma overlandjourneystothepacific pacific-northwest pacific-ocean survival thomas thomas-jefferson westward-expansion