Explore Geology
geology fieldnotes title

Devils Tower

National Monument


cover of park brochure

park geology subheading
Photo of Devils Tower
Devils Tower National Monument, Wyoming

Although Devils Tower has long been a prominent landmark in northeastern Wyoming, the origin of the mammoth rock obelisk remains somewhat obscure. Geologists agree that Devils Tower formed from molten rock forced upwards from deep within the earth. Debate continues, however, as to whether the rock cooled underground or whether Devils Tower magma reached the surface. Current research supports the conclusion that Devils Tower was not a volcano, but was injected between sedimentary rock layers and cooled underground. The characteristic furrowed columns are the result of contraction which occured during the cooling of the magma. Geologic estimates have placed the age of Devils Tower at greater than 50 million years, although it is likely that erosion uncovered the rock formations only one or two million years ago.

The unique geological attributes of Devils Tower stimulated several early preservation efforts. In 1892 Wyoming Senator Francis E. Warren persuaded the General Land Office to create a timber reserve which surrounded the Tower. Senator Warren also launched an unsuccessful effort to declare the entire area a national park. In 1906 Congress passed the Antiquities Act which empowered the President to bestow historic or prehistoric structures, and other significant historic or scientific objects. President Theodore Roosevelt quickly invoked the Antiquities Act, designating Devils Tower the nation's first National Monument in 1906. The National Park Service was created in 1916 and eventually assumed administrative control of all national monuments.

The Geological Story

  1. About 60 million years ago molten rock forced its way into overlying sedimentary rocks and cooled underground. The cooling igneous rock contracted, fracturing into columns. An earlier intrusion formed the nearby Missouri Buttes.
  2. Over millions of years the sedimentary rock eroded to expose Devil's Tower and accentuate Missouri Buttes. The Tower rises 867 feet from its base, 1,267 above the river, and 5,117 above sea level. The area of its tear-drop shaped top is 1.5 acres. Its base diameter is 1,000 feet.

park maps subheading

The General park map handed out at the visitor center is available on the park's map webpage.

For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.

photo album subheading

A general photo album for this park can be found here.

For information on other photo collections featuring National Park geology, please see the Image Sources page.

books, videos, cds subheading
Cover of Geology of Devils Tower National Monument book
Geology of Devils Tower National Monument
Robinson, Charles S. & Robert E. Davis, 1995.
Devils Tower Natural History Association
Mineral Systems Inc.
ISBN 0-913062-03-0, paperback, 96 pages, full color illustrations.

A comprehensive geologic history of Devils Tower and the immediate surrounding area, complete with definitions, color photos, maps and graphs. Not a text book; arm-chair geologists and students Junior High and up will enjoy this book.

Cover of Devils Tower, The First National Monument book

Geology of Devils Tower, The First National Monument
Robinson, Charles S., 1985.
Devils Tower Natural History Association
Reprinted with minor changes from:
Robinson, Charles S., 1956
Geology of Devils Tower National Monument: The First National Monument.
US Geological Survey Bulletin 1021-I.
paperback, 16 pages, black and white illustrations.

Cover of Geodiversity book

Geodiversity; Valuing and Conserving Abiotic Nature
Gray, Murray., 2004
John Wiley and Sons, Ltd.,
ISBN 0-47084896-0
6.5" x 9.5", paperback, 434 pages, black and white illustrations and photography.

This book focuses specifically on the geodiversity of the planet and the threats to this diversity, explains the value of inanimate nature and assesses the approaches that should be taken to conserve it. This book is for geologists and geomorphologists, nature conservationists, ecologists, landscape planners and architects. It would also make an excellent reference for undergraduates studying environmental science and related disciplines.

Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.

Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
ISBN 0-393-92407-6
9" x 10.75", paperback, 550 pages, full color throughout

The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!

Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.

geologic research subheading


For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.

The NPS maintains a searchable data base of research needs that have been identified by parks.

A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.

selected links subheading

NPS Geology and Soils Partners

NRCS logoAssociation of American State Geologists
NRCS logoGeological Society of America
NRCS logoNatural Resource Conservation Service - Soils
USGS logo U.S. Geological Survey

teacher feature subheading

Currently, we do not have a listing for any park-specific geology education programs or activities.

For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.
updated on 01/04/2005  I   http://nature.nps.gov/geology/parks/deto/index.cfm   I  Email: Webmaster
This site is best viewed in Internet Explorer 6.0 or Netscape 7.0