Depths of the earth
Subtitle: caves and cavers of the United States
By: William R. Halliday.
Edition: Rev. and enl. ed.
Publisher: Harper & Row
Published: 1976
Place of publication: New York
Language: eng
Number of pages: 432
Subjects: Caves -- United States.; Speleology.
Notes: Bibliography: p. 409-415.
Includes index.