Geologists have divided the United States into many provinces, each of
which has distinctive geologic and topographic characteristics that set
it apart from the others. One of the most intriguing and scenic of these
is the Colorado Plateaus province, referred to in this report simply as
the Colorado Plateau, or the Plateau (Hunt, C. B., 1956, fig. 1). This
province, which covers some 150,000 square miles and is not all
plateaus, as we shall see, extends from Rifle, Colo., at the northeast
to a little beyond Flagstaff, Ariz., at the southwest, and from Cedar
City, Utah, at the west nearly to Albuquerque, N. Mex., at the
southeast. Arches National Park occupies part of the Canyon Lands
Section, one of the six subdivisions of the Plateau. As the names imply,
the Canyon Lands Section of the Plateau comprises a high plateau
generally ranging in altitude from 5,000 to 7,000 feet, which has been
intricately dissected by literally thousands of canyons.
Arches National Park is drained entirely by the Colorado River, whose
deep canyon borders the park on the southeast (fig. 1). Most of the park
is drained by Salt Wash, which enters the Colorado River just southeast
of The Windows section, but the southwestern part is drained by
Courthouse Wash and Moab Canyon, whose flows join the Colorado just west
of the bridge on which U.S. Highway 163 crosses the river.
When viewed at a distance of 1 foot, the shaded relief map (fig. 1)
shows the general shape of the land surface in and near Arches National
Park to the same horizontal scale as it would appear to a person in a
spacecraft flying at a height of 250,000 feet, or about 47.5 miles. This
map was prepared from part of the reverse side of a plastic-relief
map[4] at a scale of 1:250,000 by the U.S. Army Map Service of the Moab
quadrangle, using a simple time- and money-saving method (Stacy, 1962).
[Illustration: Petroglyph figure]