Marble Mountain from the PCT by John St. Marie
The name, Marble Mountain, comes from the distinctive coloration caused by light-colored limestone along with black metamorphic rock on some peaks, giving the mountains a marbled appearance. The rock is very porous and friable (crumbling easily).
The wilderness is in the Klamath Mountains geomorphic province (a large area having similar features such as terrain and geology). The horseshoe-shaped Salmon Mountains are at the core of the wilderness with Marble Mountain being a north-trending spur ridge of the Salmons.
It is a beautiful stretch of the PCT.