Thornbury, William D. 1900- Principles of geomorphology / [by] William D. Thornbury. - 2nd ed. - New York : Wiley, c1969 - xi, 594 p. : illus., maps. ; 23 cm. Includes bibliographies. ISBN: 0471861979 Subjects--Topical Terms: Geomorphology. Dewey Class. No.: 551.4 / THP 1969