SANTA CLARA VALLEY : STRUCTURE. 33 
length, for the reason that they have a bearing on the occurrence of 
petroleum. 
The Topatopa anticline, shown at the left of the section, involves 
rocks of the Topatopa formation, which are proved to be more or less 
petroliferous by the seepages that occur on their outcrops and by the 
actual dissemination of bituminous matter through certain of the 
beds. There are, however, no wells that penetrate the formation, and 
its possibilities are as yet unknown." At the base of the Sespe forma¬ 
tion there is a layer of white sandstone which, in the gorge of Sespe 
Creek, has been found to yield an excellent supply of low-gravity 
petroleum. The well of the Union Consolidated Oil Company pene¬ 
trates the strata in this vicinity to a depth of approximately 500 or 600 
feet. The position of this well, on the regular slope of the main Topa¬ 
topa anticline, is of especial importance from the clew it may afford as 
to the occurrence of oil at this horizon under like conditions in other 
localities. 
A second feature of importance is the Cold water anticline. The 
strata on the northern face of this arch are productive, the oil being 
derived from about the same horizon as that of the well just men¬ 
tioned, miles to the northwest. The longitudinal extent of this 
anticline in an easterly direction was not determined by the writer, 
but in Boulder Creek, a little more than a mile to the east, a some¬ 
what similar fold appears nearly in the line of the Coldwater flexure. 
It may be, however, but an offset of the latter or a mere crumple on its 
flanks. It is indicated in the section and is the locus of the Ivers 
wells. Although conspicuous in the field, when plotted it is of com¬ 
parative insignificance. The oil found at this point may have no rela¬ 
tion to the minor fold, but, on the other hand, the fractures resulting 
from such a fold may have afforded a special opportunity for the accu¬ 
mulation of the petroleum. 
One of the few occurrences of oil observed in California near the 
axis of a syncline is that seen at the Kentuck wells, which are 
located in a hollow of the Sespe red beds half a mile north of Little 
Sespe Canyon. The most plausible explanation of this exceptional 
occurrence is that it is due to the effects of the Coldwater anticline, or 
possibly even of the greater Topatopa anticline, the negative effects 
of the local syncline being insufficient to overcome the influence of the 
greater folds. 
A short distance south of this depression the red sandstone of the 
Sespe formation dips steeply near the point where the axes of the folds 
exhibit a general change in strike from northeast to southeast. The 
locality is one of marked crushing and its structure is most difficult to 
decipher. The offset of a mile in the section was made here, the 
strata being again taken up in regular succession in the vicinity of the 
