BALANCED ROCK, guarding The Windows section of Arches National Park. Rock is Slick Rock Member of Entrada Sandstone resting upon crinkly bedded Dewey Bridge Member of the Entrada. White rock in foreground is Navajo Sandstone. La Sal Mountains on right skyline. (Frontispiece)
The Geologic Story of
Arches
NATIONAL PARK
By S. W. Lohman
Graphics by
John R. Stacy
GEOLOGICAL SURVEY BULLETIN 1393
UNITED STATES DEPARTMENT OF THE INTERIOR
ROGERS C. B. MORTON, Secretary
GEOLOGICAL SURVEY
V. E. McKelvey, Director
