3 The Turner thesis is older than Frederick Jackson Turner himself. Similar arguments were made by Cotton Mather and Benjamin Franklin, but Turner gave this idea its classical statement. He preserved the structure of the Teutonic “germ theory,” but argued that the European “germs” were less important than the American environment in which they grew, and specifically that “free land” encouraged the growth of democracy, capitalism and individualism. See generally Ray Billington, Westward Expansion (4th ed., New York, 1974), with a full bibliography; Lee Benson, Turner and Beard (Glencoe, 111., 1960); Ray Billington, Frederick Jackson Turner (New York, 1963); Richard Hofstadter, The Progressive Historians (New York, 1969).

4 Leading examples of the migration model are to be found in the work of Arthur Schlesinger Sr., Marcus Hansen, Oscar Handlin, and most recently Bernard Bailyn, The Peopling of British North America (New York, 1986), and Voyagers to the West: A Passage in the Peopling of America on the Eve of the Revolution (New York, 1986).