1 Stefoff, Rebecca, The American Environmental Movement (New York:Facts on File, 1995), p. 8.
2 Meriwether Lewis (1774-1809) and William Clark (1770-1838) led anexpedition from Saint Louis to the mouth of the Columbia River at the Pacific Ocean, opening up the possibility of westward expansion.
3 In 1869 the transcontinental railway was completed; by 1890 the United States Bureau of the Census announced that the American frontier had ceased to exist.
4 Tymn, Marshall (ed.), Thomas Cole's Poetry (York, PA: Liberty Cap Books), p. 103.
5 Huth, Hans, Nature and the Americans: Three Centuries of Changing Attitudes (Lincoln: University of Nebraska Press, 1957), p. 2.
6 Novak, Barbara, Nature and Culture: American Landscape and Painting 1825-1875, rev. ed. (New York: Oxford University Press, 1995), p. 171.
7 The terms "environmentalist" and "environmentalism" only came into general use in the 1970s. The environment is an ecological community as well as all the complex conditions, circumstances, and influences surrounding and affecting the development of an organism or group of organisms. These terms suggest a broader set of concerns (including toxic chemicals and nuclear waste) than those used previously-- "conservationist"and "conservationism" (Stefoff, p. 68).
8 Huth, p. 168.
9 Matilsky, Barbara, Fragile Ecologies: Contemporary Artists' Interpretations and Solutions (New York: Rizzoli in association with the Queens Museumof Art, 1992), p. 26.
10 Weinberg, Barbara H., American Impressionism and Realism: The Painting of Modern Life, 1885-1915 (New York: The Metropolitan Museum of Art),p. 140.
11 Huth, p. 193.