PUENTE HILLS: OLINDA FIELD. 
127 
The suggestion of unconformity is borne out by divergence in dip 
and strike and by the presence in the Fernando of materials unmis¬ 
takably derived from the older beds. It is, moreover, in harmony 
with observations throughout a large portion of the Coast Range. 
The fact that in the Olinda field, therefore, the Fernando formation 
lies at one point against the lower shale of the Puente formation, at 
another against the upper shale, and at still another in contact with 
the Puente sandstone, may be attributed to unconformity, to faulting, 
or to both. As already mentioned, the writer inclines to the belief 
that both of these causes have contributed their part in the develop¬ 
ment of the existing conditions. 
The principal features of structure in the Olinda field will now be 
taken up in somewhat greater detail. In the eastern third of the field, 
from the vicinity of the gulch containing Santa Fe wells Nos. 21, 32, 
36, and 38, eastward to the Columbia ground and Soquel and Tele¬ 
graph canyons, there appear to be two divergent lines of structure, the 
southern line marking the trace of the main fault, or of its alternative 
plane of unconformity between the Fernando and the older beds, 
maintaining the general trend of N. 65°—70° W., and passing across the 
lower portion of Telegraph Canyon; the northern, a line of severe 
crushing, extending more directly eastward or even a little north of 
east and following the gorge of Soquel Canyon. The northern line is 
confined wholly to the Puente formation. The combined effect of 
faulting and folding, together with the divergence in strike noted, has 
brought to the surface, north of the divisional line between Puente and 
Fernando, beds gradually lower in horizon toward the east, the pre¬ 
vailing dip being 25°-60° N. As the divergence increases additional 
crumples, some of them extremely sharp, appear in the Puente beds. 
Immediately north of the northern of the two divergent lines 
referred to above and close to the northern line of wells is located the 
axis of the general syncline that is so persistent and conspicuous a fea¬ 
ture alone: the northern border of the Olinda field. Its trend is N. 65° 
W. and it is especially prominent in the Puente sandstone. This syn¬ 
ch lie is of especial interest near the center of sec. 9, where are clustered 
several wells of the Santa Fe, Fullerton Consolidated, and Columbia 
(Puente lease No. 1) oil companies. At this point there is consider¬ 
able uncertainty regarding the stratigraphic horizon, both from the 
crumpled condition of the beds and from the lack of distinguishing 
characteristics. The Puente sandstone appears a short distance 
north of the wells, dipping to the south, but a'bout the wells the strata 
dip northward and have more the nature of arenaceous, granular, and 
muddy shale, with traces of the siliceous variety, in one instance 
faintly organic. On the whole the formation bears considerable 
resemblance to that underlying the Puente sandstone along the lower 
slopes of Soquel Canyon east of the Columbia wells (lease No. 1), and 
