Boulder on Chief Joseph Mountain
The Wallowa Mountains have been described as an island of granite and marble in a sea of basalt. Accelerated alpine erosion has almost entirely removed the vast Columbia River Basalt Formation which elsewhere still buries much of eastern Oregon. In this view from the mountain's summit, a gaudy boulder of lichened covered basalt is virtually all that remains of the basalt remnant capping 9600 ft. Chief Joseph Mountain. This is in the Eagle cap Wilderness, Oregon's largest wilderness and the largest area of above-timberline terrain in the state.