The name comes from the distinctive coloration caused by light-colored limestone along with black metamorphic rock on some peaks, giving the mountains a marbled appearance.

[5] The wilderness is in the Klamath Mountains geomorphic province (a large area having similar features such as terrain and geology).

This area of high divides, deep canyons and perennial mountain streams provides habitat for a wide variety of plant and animal life.

With more than 7,000 feet (2,100 m) of vertical relief, soils from several rock types, and abundant rain and snowfall, the diversity of ecosystems is unequaled anywhere else in the country.

[8] Fish species include summer steelhead and a spring run of king salmon in Wooley Creek, as well as resident rainbow trout in other streams in the wilderness.

[10] There are several national forest campgrounds outside the boundary and one camp inside the wilderness near Wooley Creek, named after Anthony Milne, who was a miner in the area around 1885.