90 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
PICO FIELDS. 
LOCATION. 
The Pico district, the western part of what is popularly known as 
the “Newhall district,” comprises the region of the Santa Susana 
Mountains from Tapo Canyon to Fernando Pass. The Newhall dis¬ 
trict is divided into the Pico and Elsmere districts for the purpose of 
this discussion, the geologic conditions in the two subdistricts being 
quite different. 
GEOLOGY AND STRUCTURE. 
In the body of the Santa Susana Mountains there are many flex¬ 
ures in the siliceous shale of the Modelo and in the shale and heav}^ 
sandstone of the Vaqueros. Certain of these flexures along the 
northern front of the range have become of primary economic impor¬ 
tance from the development of rich oil-bearing territory adjacent to 
their axes. With these alone the following pages have to do. (See 
PI. IV, secs. J-J', K-K', L/'-L-L', and M"-M-M'.) 
Chief among such folds is one which may be designated the Pico 
anticline. This extends for perhaps 10 miles along the northern 
front of the range. Its trend is N. 60° W. and the strata on the 
southern limb dip 25° to 30°, on the northern limb 50° to 70°. At 
the west the anticline originates in the divide between the waters 
of Pico and Salt canyons. The east end passes out of the range a 
mile or so south of Fernando Pass, the actual terminus being appar¬ 
ently in the foothills of the San Gabriel Range, or in the valley edge 
immediately adjacent. The axis of the anticline may be seen in 
any of the canyons of the Santa Susana Mountains draining to the 
Santa Clara. (See PI. IX, B.) Its trend is somewhat irregular, 
though in its entirety the fold maintains the direction given very 
closely. In the hills between Dewitt and Pico canyons a minor 
fold of the same nature branches off to the north, but this in few 
places amounts to more than a pronounced pucker in the beds 
affected by it. The Pico anticline is traceable at least to Wiley 
Canyon, and perhaps even to the forks of Rice and Gavin canyons. 
South of the main fold is a syncline which parallels it for its entire 
length. This originates at the west at about the same point as the 
anticline, in a mass of highly crumpled strata in the divide between 
Pico and Salt canyons. After a divergent course of 2 or 3 miles the 
anticline and syncline lie parallel with each other to the San Fer¬ 
nando A alley. At certain points along the syncline, as, for instance, 
at the head of Pico Canyon, there is some evidence that faulting 
has taken place immediately to the south, the strata south of the 
fault plane being downthrown and the plane itself inclined at an 
angle ol 50 to 70 . I he evidence, however, was not followed up, 
