70 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
This also is a group of wells that has been developed along the 
axis of one of the minor anticlines. (See PI. VIII, B.) The fold 
has an apparent length of barely 1 mile, and it is in the midst of a 
series of closely spaced flexures. The strike of the anticlinal axis is N. 
50° E., and the wells are distributed along the axis in almost a 
direct line. Fourteen holes have been drilled to a maximum depth 
of about 1,000 feet. The rocks penetrated are the siliceous and 
earthy shales that lie between the lower and upper Modelo sand¬ 
stones. In one or two instances, however, the lower portion of the 
upper sandstone, which consists of alternating thin sandstone and 
shale beds, has been perforated. This horizon is the highest that is 
productive in the Hopper Canyon district. The Sunset wells draw 
from strata near the base of the Modelo formation, while the San 
Cayetano wells receive their supply from the upper members of the 
Fig. 9.—Sketch map showing location of Fortuna wells with relation to the anticlinal axis. Heav> 
dots, productive wells; small circles, abandoned wells. Figures indicate numbers of wells. (See 
PI. VIII, B.) 
Vaqueros formation, which in turn are higher than any of the pro¬ 
ductive horizons in the Tar Creek and other districts alreadv 
%* 
considered. 
The maximum yield of any one of the Fortuna wells as reported 
is 75 barrels per day, but it is now generally less than 10 barrels. 
The gravity of the oil is about 14° B. Much water is pumped with 
the oil, being separated in tanks at the wells. The oil is pumped to 
storage tanks on the line of railway about 2 miles distant. 
The accompanying sketch (fig. 9) illustrates the general distribu¬ 
tion of the wells with respect to Hopper Creek and the axis of the 
anticline. 
