This valley is the surface trace of the Leech River Fault, a major regional fault that marks the contact between the oceanic basalts of the Crescent Terrane (part of Siletzia) to the south, and the metamorphic rocks of the Pacific Rim Terrane to the north.
This valley is the surface manifestation of the Leech River Fault, a significant regional fault that delineates the boundary between the oceanic basalts of the Crescent Terrane (a component of Siletzia) to the south, and the metamorphic rocks of the Pacific Rim Terrane to the north.