80 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
1,800 feet, producing nothing but water. In Shields Canyon, how¬ 
ever, west of Garberson, a trace of oil was found at 500 feet, the total 
depth of the well being 850 feet. The gravity of this oil is said to 
have been 29.5° B., but much water was encountered with it. 
TORREY-EUREKA-TAPO FIELDS. 
LOCATION. 
The district discussed in the following paragraph embraces Oak 
Ridge east of Chaffee Canyon and the western portion of the Santa 
Susana Mountains as far east as the head of Tapo Canyon. Within 
it are three productive areas—those of Torrey, Eureka, and Tapo 
canyons. 
GEOLOGY AND STRUCTURE. 
As will be gathered from the description of the geology of the 
Bardsdale district, there is a marked regularity in the stratigraphic 
succession of the formations and in the anticline into which they have 
been thrown from the west end of South Mountain to Chaffee Canyon. 
Here, however, the regularity ends. The region between Chaffee and 
Tapo canyons shows a highly complicated geologic structure, and 
there is great confusion in the stratigraphic succession, resulting from 
the presence of folds and faults and the difficulty of distinguishing 
between formations, owing to a lack of distinctive characteristics in 
the beds and to changes in the relative proportions of the coarse and 
fine sediments from point to point. 
The first break in the regularity that exists to the west appears in 
a small gulch at the foot of Oak Ridge immediately west of Chaffee 
Canyon. At this point the end of what for convenience may be 
termed the Chaffee syncline appears in “chalk rock/’ siliceous shale, 
and limestone that are believed to be of the same formation as similar 
rocks which form so great a portion of the summit of Oak Ridge, 
having been brought into this position, almost at the edge of the val¬ 
ley, by arching over the axis of the Oak Ridge-South Mountain anti¬ 
cline. The general trend of this syncline is about S. 30° E., the dip 
on either side averaging perhaps 35°, although steepening sharply as 
the axis is approached. The syncline increases in prominence as it 
crosses the drainage of Chaffee Canyon, and at the summit of the 
ridge at its head becomes a conspicuous feature in the crest line. 
The details of this syncline have not been gathered in full, but appar¬ 
ently the heavy fossiliferous sandstone which outcrops in bold escarp¬ 
ments in W iley Canyon plunges beneath the axis to reappear on the 
northeast side in the ridge that separates Chaffee and Torrey canyons. 
The conditions observed in Chaffee Canyon suggest that only the 
lower beds of the siliceous shale and u chalk rock ” are involved in the 
