STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 83 
becomes more nearly normal, both flanks will probably be found 
productive if penetrated deep enough. The surface structure indi¬ 
cates that the oil horizon plunges to a greater and greater depth 
under the whole region southeast of Casmalia Creek. The anticline 
south of Antonio is well defined and conditions favor the presence 
of oil on both this and the other anticline of the San Antonio terrace. 
The main anticline on the coast north of Point Sal, already men¬ 
tioned, is in the Yaqueros and is doubtless barren of oil. North of 
this locality the Monterey is decidedly bituminous, but no special 
circumstances point to the existence of petroleum in large quantity. 
It is quite possible that the region north of Mussel Pock, the next 
point to the north, would prove promising if the surface covering 
allowed the examination of the underlying formations and the deter¬ 
mination of anticlines. The structure seems to cause the forma¬ 
tions to plunge toward the north from the north end of the Casmalia 
Hills, and a fairly high portion of the Monterey may underlie the 
region at the mouth of the Santa Maria Valley. 
BURTON MESA. 
The plateau known as Burton Mesa is a region of numerous low 
folds in the Monterey. Along the coast the flinty shales are of low 
dip, but folded and contorted in a complex way. The folds indi¬ 
cated on the map are the most important ones, but whether or not 
they are perfectly continuous units across the mesa can not be defi¬ 
nitely ascertained on account of the covering of sand over the shale. 
The mesa appears to be structurally a continuation of the region 
near Lompoc as much as it is of the Purisima Hills, although topo¬ 
graphically it is a continuation of the latter. In the neighborhood 
of Pine and Santa Lucia canyons there is a thick series of shales 
striking far to the north of west and directing the structural lines 
across the Lompoc Valley as if to join those in that region that 
show a tendency to curve northward. West of Pine Canyon the 
strike changes. The Pine Canyon anticline shows this curving 
structure. It is a well-defined fold with broad summits and sup¬ 
ports on its flanks a considerable thickness of shale. The dip ranges 
from 10° to 30°. A characteristic appearance of the shale and dip 
on the northeastern flank is shown in PI. IV, B (p. 36). North of 
this fold occur a number of minor flexures and there is some doubt 
as to the continuity of the anticline mapped at the head of Oak 
Canyon with the well-defined fold near the coast in the vicinity of 
Canada Tortuga. A well-marked low anticline occurs near the coast 
north of Lompoc Landing and probably continues inland. It is 
probable that either one anticline of considerable importance or sev¬ 
eral small component flexures start across the mesa between Tangair 
and San Antonio Creek. The summit of all these anticlines so far 
