I SANTA CLARA VALLEY: SESPE FIELDS. 
59 
Sespe creeks. They are, therefore, to be compared with the Four- 
fork and Tar Creek wells rather than with the Kentuck, Ivers, and 
other wells farther west. Drilling was started in the upper, rusty 
division of the Sespe formation, but the source of the oil is either in 
the lowermost strata of this division or in the uppermost of the red 
beds. The wells are from 800 to 1,600 feet in depth, and their oil¬ 
bearing zones constitute the fourth general horizon at which oil has 
been found in the Sespe formation. Their source of supply is below 
that of the Fourfork wells, which is, therefore, a fifth horizon in this 
great series of red beds and their associated strata. 
While the foregoing statement doubtless covers the general condi¬ 
tions of the occurrence of oil in this vicinity, the fact that the wells 
Fig. 7.—Sketch map of F oot-of-the-IIill oil wells, showing location with relation to Little Sespe Creek 
and the geologic formations. Heavy dots, wells productive in 1902. Broken lines indicate outcrops 
around nose of anticline. Figures are numbers of wells or dip of strata. 
are in line with a minor anticlinal flexure which appears in the sum¬ 
mit of the ridge to the east must be kept in mind. It is to be ob¬ 
served also that their position is at a point where the strike of the 
beds changes rather abruptly from northerly to westerly; they are 
also in one of the inner concentric belts of strata which are involved 
in the general Topatopa anticline; thus it may be that the conditions 
are almost analogous to those of an*anticline. In conditions some¬ 
what similar to this many productive wells of the Coast Range fields 
have been found. Fig. 7 is illustrative of these conditions. The rela¬ 
tive positions of the wells are closely approximated, although the re¬ 
sults are not those of an actual survey. 
