In previous papers the writer has tried to bring out the evidence which points to the old age of the major faults and to fault-trough deposition in the Coast Ranges. In the paper on the “Tectonics of the Valle Grande” 1 the evidence for the origin by faulting of that great Cretaceous and Tertiary inland basin, of which the present Great Valley of California is a remnant, was reviewed, and in the paper entitled “Tectonics of the Coast Ranges of Middle California”2 the evidence for fault-trough deposition was discussed in greater detail. In the latter paper3 six sections across the Coast Ranges were described, and the principal old basins and land areas were outlined. These were referred to as negative and positive areas. His latest paper dealing with the tectonics of the Coast Ranges is entitled “Age of primary faulting in the Coast Ranges of California.”4 Its . . .