Marble Canyon: burrowing into the Earth

Marble Canyon, 1923

Marble Canyon, 1923, USGS

From the 1923 US Geological Survey’s Birdseye Expedition of the Grand Canyon. The full caption:

Sheer walls in Marble Canyon. The rate at which this canyon burrows its way into the earth never fails to astonish the traveler entering it for the first time. Twenty miles below its head, the walls are 2,000 feet above the river, nine-tenths being due to the rise of the plateau and one-tenth to the descent of the stream. Colorado River Survey of 1923 (Birdseye).

Picture courtesy of the USGS digital photo archive of the Birdseye Expedition. More on the expedition in Damming Grand Canyon: The 1923 USGS Colorado River Expedition by Diane Boyer and Robert Webb.