Map showing sampled radiolarian localities in the western Paleozoic and Triassic belt, Klamath Mountains, California

The western Paleozoic and Triassic belt, the largest of several major subdivisions of the Klamath Mountains geologic province, extends 300 km northward from the south end of the province in California to the north end of the province in Oregon (see inset map). The rocks of the belt are mainly sedimentary and volcanic, including tuff, cherty tuff, chert, argillite, limestone, and volcanic flows and breccia. They are of oceanic and island arc facies and are highly disarranged tectonically. The southern part of the belt is subdivided into three tectonostratigraphic terranes --- the North Fork, Hayfork, and Rattlesnake Creek terranes. The central and northern parts of the belt are undevided.