Expeditions & surveys; Railroad surveys; Canyons; Grand Coulee (Wash.)
"The Grand Coulee is about ten miles wide where it opens on the Columbia River at its northern end, which is a hundred feet above the water, and gradually widens toward the south; its walls, eight hundred feet high are formed of solid basaltic...
"This valley for the most part is wide and open." There are "spurs separating it from the Hell-Gate Valley on the south," and "separate on the north the various tributaries flowing into the Blackfoot River." Plate LXII.