374 Adventures in Scenery 



strata. The Pliocene section alone is nearly 20,000 feet thick, 

 and can be seen in its entirety between Santa Paula and the San 

 Cayetano fault. This section has been squeezed together be- 

 tween two major thrust faults on the sides. On the Oak Ridge 

 fault the movement has been about 8,000 feet toward the north, 

 whereas on the San Cayetano fault the Eocene rocks have moved 

 over two miles southward. 



The floor of Upper Ojai Valley is reached after a gentle 

 climb to an altitude of 1,500 feet above sea level. The valley 

 is structurally a "graben" (a depressed area between two faults) 

 lying between the Santa Ynez Range and Sulphur Mountain. 

 At the west end of Upper Ojai Valley the road crosses the axis 

 of a large anticline known as Black Mountain. One of the 

 faults of the San Cayetano fault zone lies at the foot of the 

 grade that leads down from the Upper to Lower Ojai Valley 

 and extends westward along the north side of Black Mountain. 

 Movement on this fault has caused the difference in altitude 

 between the Upper and Lower Ojai Valleys. 



From San Antonio Creek the road follows the Ventura 

 River through a narrow canyon at the west end of Sulphur 

 Mountain and the east end of Red Mountain. Red Mountain 

 rises high above the west bank of Ventura River, and struc- 

 turally is a large dome-like anticline. Red Mountain is almost 

 entirely circumscribed by faults. The Ventura Avenue anti- 

 cline (folded Pliocene rocks) extends westward from the valley 

 of Santa Clara River north of Saticoy to Punta Gorda, on the 

 coast 12 miles north of Ventura, a distance of 18 miles. The 

 Ventura Avenue oil field, one of the largest in California, is 

 located on this anticline, and is cut through the center at right 

 angles by the Ventura River, where the arch of the fold can be 

 plainly seen on each side. 



Ventura Oil Field and Channel Islands 



At the mouth of Ventura River, at the city of Ventura, the 

 route turns northwestward along the ocean shore for a distance 



