These two provinces are in southern California. The Transverse Ranges are a complex series of nearly west-trending mountain ranges and valleys. The province includes the San Bernardino, San Gabriel, and Santa Ynez Mountains. The most productive gold-quartz mines have been in the Frazier Mountain, Acton, and Baldwin Lake districts, where the deposits occur in schist and granitic rocks. (Sometimes Frazier Mountain is considered to be in the Coast Ranges.) Placer gold has been recovered in quantity in the San Gabriel Mountains.
The Peninsular Ranges are in Orange, western Riverside, and San Diego Counties and extend southward into Lower California. These ranges are composed largely of granitic and related rocks that are part of the southern and Lower California batholith and smaller amounts of Paleozoic and Mesozoic metamorphic rocks. The principal gold sources have been the Julian-Banner, Cuyamaca, and Pinacate districts. The primary deposits consist of gold-quartz veins in schist or granitic rocks.