A megalopolis (sometimes called a megapolis; also megaregion, or supercity) is typically defined as a chain of roughly adjacent metropolitan areas. The term was used by Patrick Geddes in his 1915 book Cities in Evolution, by Oswald Spengler in his 1918 book, The Decline of the West, and Lewis Mumford in his 1938 book, The Culture of Cities, which described it as the first stage in urban overdevelopment and social decline. Later, it was used by Jean Gottmann in 1954, to describe the chain of metropolitan areas along the northeastern seaboard of the U.S. extending from Boston, Massachusetts through New York City, Philadelphia, Baltimore, and ending in Washington, D.C. and Northern Virginia. The latter is sometimes called the "BosWash megalopolis".