78 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
colors, forms the crest of South Mountain, and extends for a consider¬ 
able distance down its western slope. It is succeeded by the Fernando 
formation. 
Minor crumples appear in South Mountain, but in the main the 
direction of dip is to the south, northerly dips being confined prac¬ 
tically to the northern side of the anticline along the edge of the 
Santa Clara Valley. 
East of Sulphur Canyon the anticline rapidly opens, and at Grimes 
Canyon (see PI. Ill, sec. D-D') it attains its greatest development. 
Here are exposed, in consequence, lower rocks than elsewhere—the 
deep-yellow sandstone that has been described as the possible correl¬ 
ative of the rusty beds in the upper portion of the Sespe formation 
north of Santa Clara River. It is overlain by red and gray banded 
beds, except on the north, where the valley has been eroded through 
these beds and into the older strata below. The yellow sandstone is 
also underlain by red and gray beds, as shown by the logs of the wells 
of the Bardsdale Crude Oil Company. Whether or not the heavy 
mass of red sandstone and conglomerate which constitutes the 
greater part of the Sespe formation north of the Santa Clara is present 
here at still greater depths is undetermined. The formations through¬ 
out give evidences of marked change within comparatively short dis¬ 
tances, and it may be that the red beds of the Sespe have practically 
disappeared. 
Overlying the red and gray beds are rocks which have been identi¬ 
fied by their fossils as a portion of the Vaqueros formation, consisting 
of conspicuous and persistent sandstone at the base and summit, and 
chocolate-colored and gray arenaceous shale, with occasional bands of 
limestone between. They bend down over the anticline between 
Garberson and Wiley canyons, and west of a point a little west of the 
mouth of Shields Canyon are adjacent to the Santa Clara Valley. At 
Wiley Canyon the axis of the anticline presents a small core of the 
underlying red and gray beds. The outer body of the Vaqueros dis¬ 
plays a slight syncline, a flexure that is the beginning, perhaps, of the 
more highly disturbed conditions that exist but a short distance 
farther east. A secondary anticline also occurs well up the slope of 
the mountain between Shields and Garberson canyons, with a length 
of slightly over a mile. 
The Vaqueros is easily confused with the Fernando formation, as 
the sandstone and conglomerate of the two formations bear consid¬ 
erable resemblance. It is probable, however, that the Fernando 
does not appear west of Torrey Canyon, but from that point eastward 
it grows in importance to the east end of the Santa Susana Moun¬ 
tains, where it is very prominent. 
Siliceous shale and “ chalk rock” of the Modelo type overlie the 
Vaqueros and form the crest of Oak Ridge for nearly its entire length. 
