372 Adventures in Scenery 



Simi Hills and Tapo Canyon Oil Field 



Near the west end of San Fernando Valley the Cretaceous 

 strata forming the Simi Hills rise abruptly from the alluvium 

 in bold cliffs. The sandstone appears as though piled in huge 

 blocks. Winding up the side of one of the small canyons ascent 

 is made to Susana Pass. From the summit Simi Valley can be 

 seen lying between the Simi Hills on the south and Oak Ridge, 

 the western extension of the Santa Susana Mountains, on the 

 north. The Simi Hills form an uplifted mass, faulted (prob- 

 ably) on the south and east sides. 



Simi Valley is a synclinal depression, Cretaceous strata being 

 gently folded into a syncline and overlain by Eocene strata. 

 One of the thickest and most fossiliferous Eocene sections in 

 California is to be found in the hills bordering Simi Valley. 

 Over 5,000 feet of sandstone, conglomerate and clay are ex- 

 posed on the north side of the valley in the road cuts between 

 Simi and Moorpark. 



Directly north of Santa Susana lies the Simi or Tapo Canyon 

 oil field. It is the only field in southern California yielding oil 

 in commercial quantities from the Eocene. The field is situ- 

 ated on an anticline extending from Tapo Canyon along the 

 north side of the valley. 



At the summit of Oak Ridge the view northward overlooks 

 the valley of Santa Clara River, another synclinal depression. 

 Directly northward is a complexly folded series of sandstones, 

 clays, and siliceous shales which forms the grass and brush cov- 

 ered mountains for about five miles east of Sespe Creek. West 

 of Sespe Creek the high and rugged Santa Paula Ridge is com- 

 posed of Eocene strata. The contact between the Eocene and 

 Pliocene is marked by a major thrust fault known as the San 

 Cayetana fault. It is plainly visible following the foot of the 

 steep south slope of Santa Paula Ridge. Oak Ridge is an anti- 

 cline having a thrust fault along its north base. 



The Bardsdale oil field, west of the mouth of Grimes Can- 

 yon, is one of a series of fields lying, along the north side of Oak 



