This online edition contains all text from the original book in its entirety, with the exception
of the section Age of the Earth, which was revised October 9, 1997, to
reflect current thinking on this topic.
Some figures have been modified to enhance legibility at screen resolutions.
All photographs are by William L. Newman, USGS.
COVER: Chromolithograph of the Grand Canyon by William Henry Holmes, printed in 1882
The printed version of this publication is one of a series of general interest publications prepared
by the U.S. Geological Survey to provide information about the earth sciences, natural resources,
and the environment. To obtain a catalog of additional titles in the series General Interest
Publications of the U.S. Geological Survey, contact:
USGS Information Services
Box 25286, Building 810
Denver Federal Center
Denver, CO 80225
303-202-4700; Fax 303-202-4693
The print version of this book can also be obtained from:
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Mail Stop SSOP
Washington, DC 20402-9328
As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally owned public lands
and natural and cultural resources. This includes fostering sound use of our land and water resources; protecting our fish, wildlife, and
biological diversity;preserving the environmental and cultural values of our national parks and historical places; and providing for the
enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to ensure that their
development is in the best interests of all our people by encouraging stewardship and citizen participation in their care. The Department also
has a major responsibility for American Indian reservation communities and for people who live in Island Territories under U.S.
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Last updated October 9, 1997
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