86 
SANTA MARIA OIL DISTRICT, CALIFORNIA. 
CONCLUSIONS REGARDING FUTURE DEVELOPMENT. 
The Purisima Hills anticlinal fold seems to offer a favorable loca¬ 
tion for oil wells along most of its soutli flank. Owing to the plung¬ 
ing of the fold toward its middle, lower and lower strata are reached 
as its extremities are approached. In the region mapped as Fer¬ 
nando, between the Hill wells and the head of Canada Laguna Seca, 
the summit beds of the Monterey are overlain by later sand and a 
well would have to be drilled to a great depth before reaching the 
oil horizon. East and west of that region the oil horizon probably 
approaches nearer to the surface. In the vicinity of Redrock Moun¬ 
tain, especially to the west of it, the conditions seem very favorable 
for the occurrence of oil. Farther east, near La Zaca Creek, a much 
lower portion of the Monterey is exposed and the rocks have been 
affected by considerable disturbance, so that it is less likely that large 
accumulations of oil will be found there. 
AREA AROUND SANTA YNEZ. 
The Santa Ynez anticline is a distinct steep fold exposed southeast 
of the town of that name. It supports on its flanks a thickness of 
at least 2,500 feet of calcareous and porcelaneous shales belonging to 
the lower portion of the Monterey. The dips at the axis range 
between 50° and 80°, but become lower toward either side. This 
fold is seemingly a structural continuation of that of the Purisima 
Hills, and it probably extends under the gravels of the region around 
Santa Ynez, its axis passing approximately under that town. But 
it is doubtful whether it is actually the same as either of the anti¬ 
clines that are shown on the map as stopping indefinitely near the 
east end of the Purisima Hills. The terraced stretch between La 
Zaca Creek and Ballard seems from the fragmentary evidence obtain¬ 
able to be in a way an undulating structural plateau formed of beds 
low in the oil-bearing shale, dipping at slight angles in various direc¬ 
tions. It is probable that the structure of the Purisima Hills is 
here interrupted, but continued in a general way beyond by the 
Santa Ynez anticline. Owing to the low position of the beds in the 
formation, the chances for finding a considerable amount of oil along 
this anticline do not seem to be as good as farther west. No sur¬ 
face evidence of petroleum was seen. Any definite statements, 
however, in regard to the region between Los Olivos and Santa 
Ynez River and between La Zaca Creek and the east edge of the area 
mapped are hazardous, for the reason that the widespread terrace 
deposits obscure practically all of the structure. 
