In the following article it is intended to set forth, so far as is possible with the information at hand, the present state of our knowledge of the geology of the Coast ranges of California. The central theme in the presentation will be a discussion of the evidence supporting the view of the pre-Cretaceous age of the uncrystalline basement rocks of this region. The evidence treated of will deal partly with some results of recent fieldwork in the southern portion of the area and partly with a more detailed restatement of the conditions found to obtain in northern California. A brief summary will also be made of the characters of the oldest rocks in the Coast ranges—the granites, crystalline schists and limestones—as well as of the Cretaceous and Tertiary formations, and of the disturbances which have taken place, as indicated by the relation of . . .