PUENTE HILLS : OLINDA FIELD. 
125 
yon field of the varying conditions attendant on the occurrence of 
petroleum within a comparatively small area. This field illustrates, 
also, the impossibility of offering a definite opinion regarding the 
probable productiveness of a particular territory, an opinion fre¬ 
quently asked of the geologist by all interested in the petroleum 
industry. 
OLINDA FIELD. 
LOCATION. 
The Olinda oil field lies 6 miles northeast of Fullerton, just within 
the southern edge of the Puente Hills, near the entrance to Soquel 
Canyon. It is connected with the main line of the Atchison, Topeka 
and Santa Fe Railway by a branch from Richfields, 4 miles south. 
As developed, the field extends along the strike of the measures, N. 
C)5°-70° W., about a mile and a half, the breath of the oil-hearing zone 
varying from one-eighth to one-third of a mile. The field is supplied 
with water from wells a mile or two out in the valley. In the immedi¬ 
ate vicinity of the productive area the principal features of topography 
include the main mass of hills, an exterior ridge which borders Tele¬ 
graph Canyon on the south and extends for a mile beyond the entrance 
to Soquel Canyon, and an inner valley separating the hills from the 
exterior ridge. Development has taken place in this valley and on 
the lower slope of the main mass of the Hills to the north. (See 
PI. XV.) 
GEOLOGY. 
The formations involved in the Olinda field embrace the upper and 
lower Puente shales, the Puente sandstone, and the Fernando con¬ 
glomerate, sandstone, and arenaceous clay. The lower Puente shale, 
the homologue of that in the Puente oil field, is exposed principally 
to the east of the developed territory, along Soquel and Carbonne 
canyons, entering but slightly into the higher portions of the ridges. 
The Puente sandstone is confined entirely to the main body of the 
hills, extending north and east from the edge of the field for many 
miles and forming the cap rock on all the higher portions as far as the 
Chino divide. The upper shale is not well developed, and it is ques¬ 
tionable whether it is present at some places in more than a trace. 
The Fernando formation constitutes the mass of the ridge south of 
Telegraph Canyon, the point of the ridge between Telegraph and 
Soquel Canyons, the hills west of the entrance to Soquel Canyon, and 
the low bench lands between the latter and Brea Ridge, at the west 
end of the field. It finally enters Brea Ridge and passes westward 
to the Brea Canyon field. It also underlies a considerable portion of 
the interior valley. These formations all extend to the region of 
Santa Ana River. 
