General Character of the Sierra Rocks.—The great mass of the Sierra Nevada consists of crystalline rocks (granites) and highly metamorphosed, tilted and dislocated sedimentary and eruptive rocks. There are less metamorphosed strata of later age (Cretaceous and Tertiary) on the western flank at and near the foot of the range, and Tertiary and Quaternary lavas and sediments deposited by streams occur on the slopes and even on crests and peaks, especially of the northern half of the range. But the great mass of the range is made up of granites and of sedimentary and eruptive rocks so highly metamorphosed as to be quite generally designated as the metamorphic rocks of the Sierra.
J. D. Whitney showed in his report on the geology of California, and added confirmation in his work on the auriferous gravels of the Sierra Nevada, that a portion of these metamorphic rocks are of Mesozoic . . .