“…This structural high, which extends about 40 Ian in a northnorthwestward direction, is defined mainly by an exposed core of Crescent Formation-Eocene pillow basalt, basaltic breccia, and basaltic sedimentary rock (Wagner, 1967a(Wagner, , 1967b. Near the northern and southern ends of the antiform the Crescent is flanked to the east and west by younger sedimentary strata of Eocene and Oligocene age.…”